diff --git a/gallery_dl/extractor/2ch.py b/gallery_dl/extractor/2ch.py
index 1f17c993..81a0a694 100644
--- a/gallery_dl/extractor/2ch.py
+++ b/gallery_dl/extractor/2ch.py
@@ -20,12 +20,12 @@ class _2chThreadExtractor(Extractor):
     directory_fmt = ("{category}", "{board}", "{thread} {title}")
     filename_fmt = "{tim}{filename:? //}.{extension}"
     archive_fmt = "{board}_{thread}_{tim}"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/res/(\d+)"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/res/(\d+)"
     example = "https://2ch.org/a/res/12345.html"
 
     def __init__(self, match):
         tld = match[1]
-        self.root = f"https://2ch.{'org' if tld == 'hk' else tld}"
+        self.root = "https://2ch." + ("org" if tld == "hk" else tld)
         Extractor.__init__(self, match)
 
     def items(self):
@@ -66,19 +66,19 @@ class _2chBoardExtractor(Extractor):
     category = "2ch"
     subcategory = "board"
     root = "https://2ch.org"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/?$"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/?$"
     example = "https://2ch.org/a/"
 
     def __init__(self, match):
         tld = match[1]
-        self.root = f"https://2ch.{'su' if tld == 'hk' else tld}"
+        self.root = "https://2ch." + ("org" if tld == "hk" else tld)
         Extractor.__init__(self, match)
 
     def items(self):
         base = f"{self.root}/{self.groups[1]}"
 
         # index page
-        url = f"{base}/index.json"
+        url = base + "/index.json"
         index = self.request_json(url)
         index["_extractor"] = _2chThreadExtractor
         for thread in index["threads"]:
diff --git a/gallery_dl/extractor/2chen.py b/gallery_dl/extractor/2chen.py
index 4456fd69..78b0aae9 100644
--- a/gallery_dl/extractor/2chen.py
+++ b/gallery_dl/extractor/2chen.py
@@ -34,7 +34,7 @@ class _2chenThreadExtractor(_2chenExtractor):
     directory_fmt = ("{category}", "{board}", "{thread} {title}")
     filename_fmt = "{time} {filename}.{extension}"
     archive_fmt = "{board}_{thread}_{no}_{time}"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/(\d+)"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/(\d+)"
     example = "https://sturdychan.help/a/12345/"
 
     def items(self):
@@ -84,7 +84,7 @@ class _2chenThreadExtractor(_2chenExtractor):
 class _2chenBoardExtractor(_2chenExtractor):
     """Extractor for 2chen boards"""
     subcategory = "board"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)(?:/catalog|/?$)"
+    pattern = BASE_PATTERN + r"/([^/?#]+)(?:/catalog|/?$)"
     example = "https://sturdychan.help/a/"
 
     def items(self):
diff --git a/gallery_dl/extractor/500px.py b/gallery_dl/extractor/500px.py
index b74bc907..748f23c4 100644
--- a/gallery_dl/extractor/500px.py
+++ b/gallery_dl/extractor/500px.py
@@ -92,7 +92,7 @@ class _500pxExtractor(Extractor):
 class _500pxUserExtractor(_500pxExtractor):
     """Extractor for photos from a user's photostream on 500px.com"""
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/(?!photo/|liked)(?:p/)?([^/?#]+)/?(?:$|[?#])"
+    pattern = BASE_PATTERN + r"/(?!photo/|liked)(?:p/)?([^/?#]+)/?(?:$|[?#])"
     example = "https://500px.com/USER"
 
     def __init__(self, match):
@@ -121,8 +121,8 @@ class _500pxGalleryExtractor(_500pxExtractor):
     """Extractor for photo galleries on 500px.com"""
     subcategory = "gallery"
     directory_fmt = ("{category}", "{user[username]}", "{gallery[name]}")
-    pattern = (rf"{BASE_PATTERN}/(?!photo/)(?:p/)?"
-               rf"([^/?#]+)/galleries/([^/?#]+)")
+    pattern = (BASE_PATTERN + r"/(?!photo/)(?:p/)?"
+               r"([^/?#]+)/galleries/([^/?#]+)")
     example = "https://500px.com/USER/galleries/GALLERY"
 
     def __init__(self, match):
@@ -178,7 +178,7 @@ class _500pxGalleryExtractor(_500pxExtractor):
 class _500pxFavoriteExtractor(_500pxExtractor):
     """Extractor for favorite 500px photos"""
     subcategory = "favorite"
-    pattern = rf"{BASE_PATTERN}/liked/?$"
+    pattern = BASE_PATTERN + r"/liked/?$"
     example = "https://500px.com/liked"
 
     def photos(self):
@@ -202,7 +202,7 @@ class _500pxFavoriteExtractor(_500pxExtractor):
 class _500pxImageExtractor(_500pxExtractor):
     """Extractor for individual images from 500px.com"""
     subcategory = "image"
-    pattern = rf"{BASE_PATTERN}/photo/(\d+)"
+    pattern = BASE_PATTERN + r"/photo/(\d+)"
     example = "https://500px.com/photo/12345/TITLE"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/8chan.py b/gallery_dl/extractor/8chan.py
index 3230182a..f7e170f6 100644
--- a/gallery_dl/extractor/8chan.py
+++ b/gallery_dl/extractor/8chan.py
@@ -69,7 +69,7 @@ class _8chanThreadExtractor(_8chanExtractor):
                      "{threadId} {subject[:50]}")
     filename_fmt = "{postId}{num:?-//} {filename[:200]}.{extension}"
     archive_fmt = "{boardUri}_{postId}_{num}"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/(?:res|last)/(\d+)"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/(?:res|last)/(\d+)"
     example = "https://8chan.moe/a/res/12345.html"
 
     def items(self):
@@ -107,7 +107,7 @@ class _8chanThreadExtractor(_8chanExtractor):
 class _8chanBoardExtractor(_8chanExtractor):
     """Extractor for 8chan boards"""
     subcategory = "board"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/(?:(\d+)\.html)?$"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/(?:(\d+)\.html)?$"
     example = "https://8chan.moe/a/"
 
     def items(self):
diff --git a/gallery_dl/extractor/agnph.py b/gallery_dl/extractor/agnph.py
index 55b17c7e..be4517a7 100644
--- a/gallery_dl/extractor/agnph.py
+++ b/gallery_dl/extractor/agnph.py
@@ -81,7 +81,7 @@ class AgnphTagExtractor(AgnphExtractor):
     subcategory = "tag"
     directory_fmt = ("{category}", "{search_tags}")
     archive_fmt = "t_{search_tags}_{id}"
-    pattern = rf"{BASE_PATTERN}/gallery/post/(?:\?([^#]+))?$"
+    pattern = BASE_PATTERN + r"/gallery/post/(?:\?([^#]+))?$"
     example = "https://agn.ph/gallery/post/?search=TAG"
 
     def __init__(self, match):
@@ -99,7 +99,7 @@ class AgnphTagExtractor(AgnphExtractor):
 class AgnphPostExtractor(AgnphExtractor):
     subcategory = "post"
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}/gallery/post/show/(\d+)"
+    pattern = BASE_PATTERN + r"/gallery/post/show/(\d+)"
     example = "https://agn.ph/gallery/post/show/12345/"
 
     def posts(self):
diff --git a/gallery_dl/extractor/ao3.py b/gallery_dl/extractor/ao3.py
index 716492e5..6c044a6c 100644
--- a/gallery_dl/extractor/ao3.py
+++ b/gallery_dl/extractor/ao3.py
@@ -118,7 +118,7 @@ class Ao3WorkExtractor(Ao3Extractor):
     directory_fmt = ("{category}", "{author}")
     filename_fmt = "{id} {title}.{extension}"
     archive_fmt = "{id}.{extension}"
-    pattern = rf"{BASE_PATTERN}/works/(\d+)"
+    pattern = BASE_PATTERN + r"/works/(\d+)"
     example = "https://archiveofourown.org/works/12345"
 
     def _init(self):
@@ -233,28 +233,28 @@ class Ao3WorkExtractor(Ao3Extractor):
 class Ao3SeriesExtractor(Ao3Extractor):
     """Extractor for AO3 works of a series"""
     subcategory = "series"
-    pattern = rf"{BASE_PATTERN}(/series/(\d+))"
+    pattern = BASE_PATTERN + r"(/series/(\d+))"
     example = "https://archiveofourown.org/series/12345"
 
 
 class Ao3TagExtractor(Ao3Extractor):
     """Extractor for AO3 works by tag"""
     subcategory = "tag"
-    pattern = rf"{BASE_PATTERN}(/tags/([^/?#]+)/works(?:/?\?.+)?)"
+    pattern = BASE_PATTERN + r"(/tags/([^/?#]+)/works(?:/?\?.+)?)"
     example = "https://archiveofourown.org/tags/TAG/works"
 
 
 class Ao3SearchExtractor(Ao3Extractor):
     """Extractor for AO3 search results"""
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}(/works/search/?\?.+)"
+    pattern = BASE_PATTERN + r"(/works/search/?\?.+)"
     example = "https://archiveofourown.org/works/search?work_search[query]=air"
 
 
 class Ao3UserExtractor(Dispatch, Ao3Extractor):
     """Extractor for an AO3 user profile"""
-    pattern = (rf"{BASE_PATTERN}/users/([^/?#]+(?:/pseuds/[^/?#]+)?)"
-               rf"(?:/profile)?/?(?:$|\?|#)")
+    pattern = (BASE_PATTERN + r"/users/([^/?#]+(?:/pseuds/[^/?#]+)?)"
+               r"(?:/profile)?/?(?:$|\?|#)")
     example = "https://archiveofourown.org/users/USER"
 
     def items(self):
@@ -269,16 +269,16 @@ class Ao3UserExtractor(Dispatch, Ao3Extractor):
 class Ao3UserWorksExtractor(Ao3Extractor):
     """Extractor for works of an AO3 user"""
     subcategory = "user-works"
-    pattern = (rf"{BASE_PATTERN}(/users/([^/?#]+)/(?:pseuds/([^/?#]+)/)?"
-               rf"works(?:/?\?.+)?)")
+    pattern = (BASE_PATTERN + r"(/users/([^/?#]+)/(?:pseuds/([^/?#]+)/)?"
+               r"works(?:/?\?.+)?)")
     example = "https://archiveofourown.org/users/USER/works"
 
 
 class Ao3UserSeriesExtractor(Ao3Extractor):
     """Extractor for series of an AO3 user"""
     subcategory = "user-series"
-    pattern = (rf"{BASE_PATTERN}(/users/([^/?#]+)/(?:pseuds/([^/?#]+)/)?"
-               rf"series(?:/?\?.+)?)")
+    pattern = (BASE_PATTERN + r"(/users/([^/?#]+)/(?:pseuds/([^/?#]+)/)?"
+               r"series(?:/?\?.+)?)")
     example = "https://archiveofourown.org/users/USER/series"
 
     def items(self):
@@ -297,8 +297,8 @@ class Ao3UserSeriesExtractor(Ao3Extractor):
 class Ao3UserBookmarkExtractor(Ao3Extractor):
     """Extractor for bookmarked works of an AO3 user"""
     subcategory = "user-bookmark"
-    pattern = (rf"{BASE_PATTERN}(/users/([^/?#]+)/(?:pseuds/([^/?#]+)/)?"
-               rf"bookmarks(?:/?\?.+)?)")
+    pattern = (BASE_PATTERN + r"(/users/([^/?#]+)/(?:pseuds/([^/?#]+)/)?"
+               r"bookmarks(?:/?\?.+)?)")
     example = "https://archiveofourown.org/users/USER/bookmarks"
 
     def items(self):
@@ -308,7 +308,7 @@ class Ao3UserBookmarkExtractor(Ao3Extractor):
 class Ao3SubscriptionsExtractor(Ao3Extractor):
     """Extractor for your AO3 account's subscriptions"""
     subcategory = "subscriptions"
-    pattern = rf"{BASE_PATTERN}(/users/([^/?#]+)/subscriptions(?:/?\?.+)?)"
+    pattern = BASE_PATTERN + r"(/users/([^/?#]+)/subscriptions(?:/?\?.+)?)"
     example = "https://archiveofourown.org/users/USER/subscriptions"
 
     def items(self):
diff --git a/gallery_dl/extractor/arcalive.py b/gallery_dl/extractor/arcalive.py
index f950d14b..d48e4f5a 100644
--- a/gallery_dl/extractor/arcalive.py
+++ b/gallery_dl/extractor/arcalive.py
@@ -36,7 +36,7 @@ class ArcalivePostExtractor(ArcaliveExtractor):
     directory_fmt = ("{category}", "{boardSlug}")
     filename_fmt = "{id}_{num}{title:? //[b:230]}.{extension}"
     archive_fmt = "{id}_{num}"
-    pattern = rf"{BASE_PATTERN}/b/(?:\w+)/(\d+)"
+    pattern = BASE_PATTERN + r"/b/(?:\w+)/(\d+)"
     example = "https://arca.live/b/breaking/123456789"
 
     def items(self):
@@ -84,7 +84,7 @@ class ArcalivePostExtractor(ArcaliveExtractor):
                 url = src
 
             fallback = ()
-            query = f"?type=orig&{query}"
+            query = "?type=orig&" + query
             if orig := text.extr(media, 'data-orig="', '"'):
                 path, _, ext = url.rpartition(".")
                 if ext != orig:
@@ -115,7 +115,7 @@ class ArcalivePostExtractor(ArcaliveExtractor):
 class ArcaliveBoardExtractor(ArcaliveExtractor):
     """Extractor for an arca.live board's posts"""
     subcategory = "board"
-    pattern = rf"{BASE_PATTERN}/b/([^/?#]+)/?(?:\?([^#]+))?$"
+    pattern = BASE_PATTERN + r"/b/([^/?#]+)/?(?:\?([^#]+))?$"
     example = "https://arca.live/b/breaking"
 
     def articles(self):
@@ -127,7 +127,7 @@ class ArcaliveBoardExtractor(ArcaliveExtractor):
 class ArcaliveUserExtractor(ArcaliveExtractor):
     """Extractor for an arca.live users's posts"""
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/u/@([^/?#]+)/?(?:\?([^#]+))?$"
+    pattern = BASE_PATTERN + r"/u/@([^/?#]+)/?(?:\?([^#]+))?$"
     example = "https://arca.live/u/@USER"
 
     def articles(self):
@@ -169,8 +169,11 @@ class ArcaliveAPI():
             return data
 
         self.log.debug("Server response: %s", data)
-        msg = f": {msg}" if (msg := data.get("message")) else ""
-        raise exception.AbortExtraction(f"API request failed{msg}")
+        if msg := data.get("message"):
+            msg = "API request failed: " + msg
+        else:
+            msg = "API request failed"
+        raise exception.AbortExtraction(msg)
 
     def _pagination(self, endpoint, params, key):
         while True:
diff --git a/gallery_dl/extractor/arena.py b/gallery_dl/extractor/arena.py
index ada2fa1d..6f3fa96d 100644
--- a/gallery_dl/extractor/arena.py
+++ b/gallery_dl/extractor/arena.py
@@ -24,8 +24,8 @@ class ArenaChannelExtractor(GalleryExtractor):
     example = "https://are.na/evan-collins-1522646491/cassette-futurism"
 
     def metadata(self, page):
-        channel = self.request_json(
-            f"https://api.are.na/v2/channels/{self.groups[0]}")
+        url = "https://api.are.na/v2/channels/" + self.groups[0]
+        channel = self.request_json(url)
 
         channel["date"] = self.parse_datetime_iso(
             channel["created_at"])
diff --git a/gallery_dl/extractor/artstation.py b/gallery_dl/extractor/artstation.py
index f1b55ce8..9c0f5ed4 100644
--- a/gallery_dl/extractor/artstation.py
+++ b/gallery_dl/extractor/artstation.py
@@ -95,7 +95,7 @@ class ArtstationExtractor(Extractor):
             if not self.external:
                 return
             asset["extension"] = "mp4"
-            return f"ytdl:{url}"
+            return "ytdl:" + url
 
         self.log.debug(player)
         self.log.warning("Failed to extract embedded player URL (%s)",
@@ -328,9 +328,9 @@ class ArtstationChallengeExtractor(ArtstationExtractor):
 
     def items(self):
         base = f"{self.root}/contests/_/challenges/{self.challenge_id}"
-        challenge_url = f"{base}.json"
-        submission_url = f"{base}/submissions.json"
-        update_url = f"{self.root}/contests/submission_updates.json"
+        challenge_url = base + ".json"
+        submission_url = base + "/submissions.json"
+        update_url = self.root + "/contests/submission_updates.json"
 
         challenge = self.request_json(challenge_url)
         yield Message.Directory, "", {"challenge": challenge}
@@ -388,7 +388,7 @@ class ArtstationSearchExtractor(ArtstationExtractor):
                     "value" : value.split(","),
                 })
 
-        url = f"{self.root}/api/v2/search/projects.json"
+        url = self.root + "/api/v2/search/projects.json"
         data = {
             "query"            : self.query,
             "page"             : None,
@@ -419,7 +419,7 @@ class ArtstationArtworkExtractor(ArtstationExtractor):
         return {"artwork": self.query}
 
     def projects(self):
-        url = f"{self.root}/projects.json"
+        url = self.root + "/projects.json"
         return self._pagination(url, self.query.copy())
 
 
diff --git a/gallery_dl/extractor/aryion.py b/gallery_dl/extractor/aryion.py
index 5e5d1f25..686adb8e 100644
--- a/gallery_dl/extractor/aryion.py
+++ b/gallery_dl/extractor/aryion.py
@@ -211,7 +211,7 @@ class AryionGalleryExtractor(AryionExtractor):
     """Extractor for a user's gallery on eka's portal"""
     subcategory = "gallery"
     categorytransfer = True
-    pattern = rf"{BASE_PATTERN}/(?:gallery/|user/|latest.php\?name=)([^/?#]+)"
+    pattern = BASE_PATTERN + r"/(?:gallery/|user/|latest.php\?name=)([^/?#]+)"
     example = "https://aryion.com/g4/gallery/USER"
 
     def _init(self):
@@ -238,7 +238,7 @@ class AryionFavoriteExtractor(AryionExtractor):
     subcategory = "favorite"
     directory_fmt = ("{category}", "{user!l}", "favorites", "{folder}")
     archive_fmt = "f_{user}_{id}"
-    pattern = rf"{BASE_PATTERN}/favorites/([^/?#]+)(?:/([^?#]+))?"
+    pattern = BASE_PATTERN + r"/favorites/([^/?#]+)(?:/([^?#]+))?"
     example = "https://aryion.com/g4/favorites/USER"
 
     def _init(self):
@@ -253,7 +253,7 @@ class AryionWatchExtractor(AryionExtractor):
     """Extractor for your watched users and tags"""
     subcategory = "watch"
     directory_fmt = ("{category}", "{user!l}",)
-    pattern = rf"{BASE_PATTERN}/messagepage\.php()"
+    pattern = BASE_PATTERN + r"/messagepage\.php()"
     example = "https://aryion.com/g4/messagepage.php"
 
     def posts(self):
@@ -271,7 +271,7 @@ class AryionTagExtractor(AryionExtractor):
     subcategory = "tag"
     directory_fmt = ("{category}", "tags", "{search_tags}")
     archive_fmt = "t_{search_tags}_{id}"
-    pattern = rf"{BASE_PATTERN}/tags\.php\?([^#]+)"
+    pattern = BASE_PATTERN + r"/tags\.php\?([^#]+)"
     example = "https://aryion.com/g4/tags.php?tag=TAG"
 
     def _init(self):
@@ -293,7 +293,7 @@ class AryionSearchExtractor(AryionExtractor):
                      "{search[q]|search[tags]|search[user]}")
     archive_fmt = ("s_{search[prefix]}"
                    "{search[q]|search[tags]|search[user]}_{id}")
-    pattern = rf"{BASE_PATTERN}/search\.php\?([^#]+)"
+    pattern = BASE_PATTERN + r"/search\.php\?([^#]+)"
     example = "https://aryion.com/g4/search.php?q=TEXT&tags=TAGS&user=USER"
 
     def metadata(self):
@@ -313,7 +313,7 @@ class AryionSearchExtractor(AryionExtractor):
 class AryionPostExtractor(AryionExtractor):
     """Extractor for individual posts on eka's portal"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/view/(\d+)"
+    pattern = BASE_PATTERN + r"/view/(\d+)"
     example = "https://aryion.com/g4/view/12345"
 
     def posts(self):
diff --git a/gallery_dl/extractor/audiochan.py b/gallery_dl/extractor/audiochan.py
index b708ce76..ccd05f35 100644
--- a/gallery_dl/extractor/audiochan.py
+++ b/gallery_dl/extractor/audiochan.py
@@ -103,7 +103,7 @@ class AudiochanExtractor(Extractor):
 
 class AudiochanAudioExtractor(AudiochanExtractor):
     subcategory = "audio"
-    pattern = rf"{BASE_PATTERN}/a/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/a/([^/?#]+)"
     example = "https://audiochan.com/a/SLUG"
 
     def posts(self):
@@ -114,7 +114,7 @@ class AudiochanAudioExtractor(AudiochanExtractor):
 
 class AudiochanUserExtractor(AudiochanExtractor):
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/u/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/u/([^/?#]+)"
     example = "https://audiochan.com/u/USER"
 
     def posts(self):
@@ -130,7 +130,7 @@ class AudiochanUserExtractor(AudiochanExtractor):
 
 class AudiochanCollectionExtractor(AudiochanExtractor):
     subcategory = "collection"
-    pattern = rf"{BASE_PATTERN}/c/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/c/([^/?#]+)"
     example = "https://audiochan.com/c/SLUG"
 
     def posts(self):
@@ -146,7 +146,7 @@ class AudiochanCollectionExtractor(AudiochanExtractor):
 
 class AudiochanSearchExtractor(AudiochanExtractor):
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/search/?\?([^#]+)"
+    pattern = BASE_PATTERN + r"/search/?\?([^#]+)"
     example = "https://audiochan.com/search?q=QUERY"
 
     def posts(self):
diff --git a/gallery_dl/extractor/batoto.py b/gallery_dl/extractor/batoto.py
index f8e803bf..1042d789 100644
--- a/gallery_dl/extractor/batoto.py
+++ b/gallery_dl/extractor/batoto.py
@@ -80,7 +80,7 @@ class BatotoBase():
 class BatotoChapterExtractor(BatotoBase, ChapterExtractor):
     """Extractor for batoto manga chapters"""
     archive_fmt = "{chapter_id}_{page}"
-    pattern = rf"{BASE_PATTERN}/(?:title/[^/?#]+|chapter)/(\d+)"
+    pattern = BASE_PATTERN + r"/(?:title/[^/?#]+|chapter)/(\d+)"
     example = "https://xbato.org/title/12345-MANGA/54321"
 
     def __init__(self, match):
@@ -139,8 +139,8 @@ class BatotoMangaExtractor(BatotoBase, MangaExtractor):
     """Extractor for batoto manga"""
     reverse = False
     chapterclass = BatotoChapterExtractor
-    pattern = (rf"{BASE_PATTERN}"
-               rf"/(?:title/(\d+)[^/?#]*|series/(\d+)(?:/[^/?#]*)?)/?$")
+    pattern = (BASE_PATTERN +
+               r"/(?:title/(\d+)[^/?#]*|series/(\d+)(?:/[^/?#]*)?)/?$")
     example = "https://xbato.org/title/12345-MANGA/"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/bbc.py b/gallery_dl/extractor/bbc.py
index cb357d1c..9d4854d7 100644
--- a/gallery_dl/extractor/bbc.py
+++ b/gallery_dl/extractor/bbc.py
@@ -21,7 +21,7 @@ class BbcGalleryExtractor(GalleryExtractor):
     directory_fmt = ("{category}", "{path:I}")
     filename_fmt = "{num:>02}.{extension}"
     archive_fmt = "{programme}_{num}"
-    pattern = rf"{BASE_PATTERN}[^/?#]+(?!/galleries)(?:/[^/?#]+)?)$"
+    pattern = BASE_PATTERN + r"[^/?#]+(?!/galleries)(?:/[^/?#]+)?)$"
     example = "https://www.bbc.co.uk/programmes/PATH"
 
     def metadata(self, page):
@@ -71,7 +71,7 @@ class BbcProgrammeExtractor(Extractor):
     category = "bbc"
     subcategory = "programme"
     root = "https://www.bbc.co.uk"
-    pattern = rf"{BASE_PATTERN}[^/?#]+/galleries)(?:/?\?page=(\d+))?"
+    pattern = BASE_PATTERN + r"[^/?#]+/galleries)(?:/?\?page=(\d+))?"
     example = "https://www.bbc.co.uk/programmes/ID/galleries"
 
     def items(self):
diff --git a/gallery_dl/extractor/bellazon.py b/gallery_dl/extractor/bellazon.py
index 33f4ad31..b9ec3d96 100644
--- a/gallery_dl/extractor/bellazon.py
+++ b/gallery_dl/extractor/bellazon.py
@@ -24,7 +24,7 @@ class BellazonExtractor(Extractor):
     archive_fmt = "{post[id]}/{id}_{filename}"
 
     def items(self):
-        native = (f"{self.root}/", f"{self.root[6:]}/")
+        native = (self.root + "/", self.root[6:] + "/")
         extract_urls = text.re(
             r'(?s)<('
             r'(?:video .*?<source [^>]*?src|a [^>]*?href)="([^"]+).*?</a>'
@@ -82,7 +82,7 @@ class BellazonExtractor(Extractor):
                         dc["extension"] = text.ext_from_url(url)
 
                     if url[0] == "/":
-                        url = f"https:{url}"
+                        url = "https:" + url
                     yield Message.Url, url, dc
 
                 else:
@@ -91,10 +91,10 @@ class BellazonExtractor(Extractor):
                     yield Message.Queue, url, data
 
     def _pagination(self, base, pnum=None):
-        base = f"{self.root}{base}"
+        base = self.root + base
 
         if pnum is None:
-            url = f"{base}/"
+            url = base + "/"
             pnum = 1
         else:
             url = f"{base}/page/{pnum}/"
@@ -112,7 +112,7 @@ class BellazonExtractor(Extractor):
             url = f"{base}/page/{pnum}/"
 
     def _pagination_reverse(self, base, pnum=None):
-        base = f"{self.root}{base}"
+        base = self.root + base
 
         url = f"{base}/page/{'9999' if pnum is None else pnum}/"
         with self.request(url) as response:
@@ -127,7 +127,7 @@ class BellazonExtractor(Extractor):
             if pnum > 1:
                 url = f"{base}/page/{pnum}/"
             elif pnum == 1:
-                url = f"{base}/"
+                url = base + "/"
             else:
                 return
 
@@ -192,15 +192,15 @@ class BellazonExtractor(Extractor):
 
 class BellazonPostExtractor(BellazonExtractor):
     subcategory = "post"
-    pattern = (rf"{BASE_PATTERN}(/topic/\d+-[\w-]+(?:/page/\d+)?)"
-               rf"/?#(?:findC|c)omment-(\d+)")
+    pattern = (BASE_PATTERN + r"(/topic/\d+-[\w-]+(?:/page/\d+)?)"
+               r"/?#(?:findC|c)omment-(\d+)")
     example = "https://www.bellazon.com/main/topic/123-SLUG/#findComment-12345"
 
     def posts(self):
         path, post_id = self.groups
-        page = self.request(f"{self.root}{path}").text
+        page = self.request(self.root + path).text
 
-        pos = page.find(f'id="elComment_{post_id}')
+        pos = page.find('id="elComment_' + post_id)
         if pos < 0:
             raise exception.NotFoundError("post")
         html = text.extract(page, "<article ", "</article>", pos-100)[0]
@@ -211,7 +211,7 @@ class BellazonPostExtractor(BellazonExtractor):
 
 class BellazonThreadExtractor(BellazonExtractor):
     subcategory = "thread"
-    pattern = rf"{BASE_PATTERN}(/topic/\d+-[\w-]+)(?:/page/(\d+))?"
+    pattern = BASE_PATTERN + r"(/topic/\d+-[\w-]+)(?:/page/(\d+))?"
     example = "https://www.bellazon.com/main/topic/123-SLUG/"
 
     def posts(self):
@@ -236,7 +236,7 @@ class BellazonThreadExtractor(BellazonExtractor):
 
 class BellazonForumExtractor(BellazonExtractor):
     subcategory = "forum"
-    pattern = rf"{BASE_PATTERN}(/forum/\d+-[\w-]+)(?:/page/(\d+))?"
+    pattern = BASE_PATTERN + r"(/forum/\d+-[\w-]+)(?:/page/(\d+))?"
     example = "https://www.bellazon.com/main/forum/123-SLUG/"
 
     def items(self):
diff --git a/gallery_dl/extractor/bilibili.py b/gallery_dl/extractor/bilibili.py
index fe10150f..d9a942df 100644
--- a/gallery_dl/extractor/bilibili.py
+++ b/gallery_dl/extractor/bilibili.py
@@ -146,7 +146,7 @@ class BilibiliAPI():
             except Exception:
                 if "window._riskdata_" not in page:
                     raise exception.AbortExtraction(
-                        f"{article_id}: Unable to extract INITIAL_STATE data")
+                        article_id + ": Unable to extract INITIAL_STATE data")
             self.extractor.wait(seconds=300)
 
     def user_favlist(self):
diff --git a/gallery_dl/extractor/blogger.py b/gallery_dl/extractor/blogger.py
index 766272f9..513a7689 100644
--- a/gallery_dl/extractor/blogger.py
+++ b/gallery_dl/extractor/blogger.py
@@ -117,7 +117,7 @@ BASE_PATTERN = BloggerExtractor.update({
 class BloggerPostExtractor(BloggerExtractor):
     """Extractor for a single blog post"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}(/\d\d\d\d/\d\d/[^/?#]+\.html)"
+    pattern = BASE_PATTERN + r"(/\d\d\d\d/\d\d/[^/?#]+\.html)"
     example = "https://BLOG.blogspot.com/1970/01/TITLE.html"
 
     def posts(self, blog):
@@ -127,7 +127,7 @@ class BloggerPostExtractor(BloggerExtractor):
 class BloggerBlogExtractor(BloggerExtractor):
     """Extractor for an entire Blogger blog"""
     subcategory = "blog"
-    pattern = rf"{BASE_PATTERN}/?$"
+    pattern = BASE_PATTERN + r"/?$"
     example = "https://BLOG.blogspot.com/"
 
     def posts(self, blog):
@@ -137,7 +137,7 @@ class BloggerBlogExtractor(BloggerExtractor):
 class BloggerSearchExtractor(BloggerExtractor):
     """Extractor for Blogger search resuls"""
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/search/?\?q=([^&#]+)"
+    pattern = BASE_PATTERN + r"/search/?\?q=([^&#]+)"
     example = "https://BLOG.blogspot.com/search?q=QUERY"
 
     def metadata(self):
@@ -151,7 +151,7 @@ class BloggerSearchExtractor(BloggerExtractor):
 class BloggerLabelExtractor(BloggerExtractor):
     """Extractor for Blogger posts by label"""
     subcategory = "label"
-    pattern = rf"{BASE_PATTERN}/search/label/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/search/label/([^/?#]+)"
     example = "https://BLOG.blogspot.com/search/label/LABEL"
 
     def metadata(self):
diff --git a/gallery_dl/extractor/bluesky.py b/gallery_dl/extractor/bluesky.py
index c981608b..6e7b3442 100644
--- a/gallery_dl/extractor/bluesky.py
+++ b/gallery_dl/extractor/bluesky.py
@@ -14,7 +14,7 @@ from ..cache import cache, memcache
 
 BASE_PATTERN = (r"(?:https?://)?"
                 r"(?:(?:www\.)?(?:c|[fv]x)?bs[ky]y[ex]?\.app|main\.bsky\.dev)")
-USER_PATTERN = rf"{BASE_PATTERN}/profile/([^/?#]+)"
+USER_PATTERN = BASE_PATTERN + r"/profile/([^/?#]+)"
 
 
 class BlueskyExtractor(Extractor):
@@ -216,7 +216,7 @@ class BlueskyExtractor(Extractor):
 
 
 class BlueskyUserExtractor(Dispatch, BlueskyExtractor):
-    pattern = rf"{USER_PATTERN}$"
+    pattern = USER_PATTERN + r"$"
     example = "https://bsky.app/profile/HANDLE"
 
     def items(self):
@@ -237,7 +237,7 @@ class BlueskyUserExtractor(Dispatch, BlueskyExtractor):
 
 class BlueskyPostsExtractor(BlueskyExtractor):
     subcategory = "posts"
-    pattern = rf"{USER_PATTERN}/posts"
+    pattern = USER_PATTERN + r"/posts"
     example = "https://bsky.app/profile/HANDLE/posts"
 
     def posts(self):
@@ -247,7 +247,7 @@ class BlueskyPostsExtractor(BlueskyExtractor):
 
 class BlueskyRepliesExtractor(BlueskyExtractor):
     subcategory = "replies"
-    pattern = rf"{USER_PATTERN}/replies"
+    pattern = USER_PATTERN + r"/replies"
     example = "https://bsky.app/profile/HANDLE/replies"
 
     def posts(self):
@@ -257,7 +257,7 @@ class BlueskyRepliesExtractor(BlueskyExtractor):
 
 class BlueskyMediaExtractor(BlueskyExtractor):
     subcategory = "media"
-    pattern = rf"{USER_PATTERN}/media"
+    pattern = USER_PATTERN + r"/media"
     example = "https://bsky.app/profile/HANDLE/media"
 
     def posts(self):
@@ -267,7 +267,7 @@ class BlueskyMediaExtractor(BlueskyExtractor):
 
 class BlueskyVideoExtractor(BlueskyExtractor):
     subcategory = "video"
-    pattern = rf"{USER_PATTERN}/video"
+    pattern = USER_PATTERN + r"/video"
     example = "https://bsky.app/profile/HANDLE/video"
 
     def posts(self):
@@ -277,7 +277,7 @@ class BlueskyVideoExtractor(BlueskyExtractor):
 
 class BlueskyLikesExtractor(BlueskyExtractor):
     subcategory = "likes"
-    pattern = rf"{USER_PATTERN}/likes"
+    pattern = USER_PATTERN + r"/likes"
     example = "https://bsky.app/profile/HANDLE/likes"
 
     def posts(self):
@@ -288,7 +288,7 @@ class BlueskyLikesExtractor(BlueskyExtractor):
 
 class BlueskyFeedExtractor(BlueskyExtractor):
     subcategory = "feed"
-    pattern = rf"{USER_PATTERN}/feed/([^/?#]+)"
+    pattern = USER_PATTERN + r"/feed/([^/?#]+)"
     example = "https://bsky.app/profile/HANDLE/feed/NAME"
 
     def posts(self):
@@ -298,7 +298,7 @@ class BlueskyFeedExtractor(BlueskyExtractor):
 
 class BlueskyListExtractor(BlueskyExtractor):
     subcategory = "list"
-    pattern = rf"{USER_PATTERN}/lists/([^/?#]+)"
+    pattern = USER_PATTERN + r"/lists/([^/?#]+)"
     example = "https://bsky.app/profile/HANDLE/lists/ID"
 
     def posts(self):
@@ -308,7 +308,7 @@ class BlueskyListExtractor(BlueskyExtractor):
 
 class BlueskyFollowingExtractor(BlueskyExtractor):
     subcategory = "following"
-    pattern = rf"{USER_PATTERN}/follows"
+    pattern = USER_PATTERN + r"/follows"
     example = "https://bsky.app/profile/HANDLE/follows"
 
     def items(self):
@@ -320,7 +320,7 @@ class BlueskyFollowingExtractor(BlueskyExtractor):
 
 class BlueskyPostExtractor(BlueskyExtractor):
     subcategory = "post"
-    pattern = rf"{USER_PATTERN}/post/([^/?#]+)"
+    pattern = USER_PATTERN + r"/post/([^/?#]+)"
     example = "https://bsky.app/profile/HANDLE/post/ID"
 
     def posts(self):
@@ -330,7 +330,7 @@ class BlueskyPostExtractor(BlueskyExtractor):
 
 class BlueskyInfoExtractor(BlueskyExtractor):
     subcategory = "info"
-    pattern = rf"{USER_PATTERN}/info"
+    pattern = USER_PATTERN + r"/info"
     example = "https://bsky.app/profile/HANDLE/info"
 
     def items(self):
@@ -342,7 +342,7 @@ class BlueskyInfoExtractor(BlueskyExtractor):
 class BlueskyAvatarExtractor(BlueskyExtractor):
     subcategory = "avatar"
     filename_fmt = "avatar_{post_id}.{extension}"
-    pattern = rf"{USER_PATTERN}/avatar"
+    pattern = USER_PATTERN + r"/avatar"
     example = "https://bsky.app/profile/HANDLE/avatar"
 
     def posts(self):
@@ -352,7 +352,7 @@ class BlueskyAvatarExtractor(BlueskyExtractor):
 class BlueskyBackgroundExtractor(BlueskyExtractor):
     subcategory = "background"
     filename_fmt = "background_{post_id}.{extension}"
-    pattern = rf"{USER_PATTERN}/ba(?:nner|ckground)"
+    pattern = USER_PATTERN + r"/ba(?:nner|ckground)"
     example = "https://bsky.app/profile/HANDLE/banner"
 
     def posts(self):
@@ -361,7 +361,7 @@ class BlueskyBackgroundExtractor(BlueskyExtractor):
 
 class BlueskySearchExtractor(BlueskyExtractor):
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/search(?:/|\?q=)(.+)"
+    pattern = BASE_PATTERN + r"/search(?:/|\?q=)(.+)"
     example = "https://bsky.app/search?q=QUERY"
 
     def posts(self):
@@ -371,7 +371,7 @@ class BlueskySearchExtractor(BlueskyExtractor):
 
 class BlueskyHashtagExtractor(BlueskyExtractor):
     subcategory = "hashtag"
-    pattern = rf"{BASE_PATTERN}/hashtag/([^/?#]+)(?:/(top|latest))?"
+    pattern = BASE_PATTERN + r"/hashtag/([^/?#]+)(?:/(top|latest))?"
     example = "https://bsky.app/hashtag/NAME"
 
     def posts(self):
@@ -381,7 +381,7 @@ class BlueskyHashtagExtractor(BlueskyExtractor):
 
 class BlueskyBookmarkExtractor(BlueskyExtractor):
     subcategory = "bookmark"
-    pattern = rf"{BASE_PATTERN}/saved"
+    pattern = BASE_PATTERN + r"/saved"
     example = "https://bsky.app/saved"
 
     def posts(self):
diff --git a/gallery_dl/extractor/boosty.py b/gallery_dl/extractor/boosty.py
index 5add7683..01ecf59f 100644
--- a/gallery_dl/extractor/boosty.py
+++ b/gallery_dl/extractor/boosty.py
@@ -163,7 +163,7 @@ class BoostyExtractor(Extractor):
 class BoostyUserExtractor(BoostyExtractor):
     """Extractor for boosty.to user profiles"""
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)(?:\?([^#]+))?$"
+    pattern = BASE_PATTERN + r"/([^/?#]+)(?:\?([^#]+))?$"
     example = "https://boosty.to/USER"
 
     def posts(self):
@@ -179,7 +179,7 @@ class BoostyMediaExtractor(BoostyExtractor):
     subcategory = "media"
     directory_fmt = "{category}", "{user[blogUrl]} ({user[id]})", "media"
     filename_fmt = "{post[id]}_{num}.{extension}"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/media/([^/?#]+)(?:\?([^#]+))?"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/media/([^/?#]+)(?:\?([^#]+))?"
     example = "https://boosty.to/USER/media/all"
 
     def posts(self):
@@ -192,7 +192,7 @@ class BoostyMediaExtractor(BoostyExtractor):
 class BoostyFeedExtractor(BoostyExtractor):
     """Extractor for your boosty.to subscription feed"""
     subcategory = "feed"
-    pattern = rf"{BASE_PATTERN}/(?:\?([^#]+))?(?:$|#)"
+    pattern = BASE_PATTERN + r"/(?:\?([^#]+))?(?:$|#)"
     example = "https://boosty.to/"
 
     def posts(self):
@@ -203,7 +203,7 @@ class BoostyFeedExtractor(BoostyExtractor):
 class BoostyPostExtractor(BoostyExtractor):
     """Extractor for boosty.to posts"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/posts/([0-9a-f-]+)"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/posts/([0-9a-f-]+)"
     example = "https://boosty.to/USER/posts/01234567-89ab-cdef-0123-456789abcd"
 
     def posts(self):
@@ -216,7 +216,7 @@ class BoostyPostExtractor(BoostyExtractor):
 class BoostyFollowingExtractor(BoostyExtractor):
     """Extractor for your boosty.to subscribed users"""
     subcategory = "following"
-    pattern = rf"{BASE_PATTERN}/app/settings/subscriptions"
+    pattern = BASE_PATTERN + r"/app/settings/subscriptions"
     example = "https://boosty.to/app/settings/subscriptions"
 
     def items(self):
@@ -231,7 +231,7 @@ class BoostyDirectMessagesExtractor(BoostyExtractor):
     subcategory = "direct-messages"
     directory_fmt = ("{category}", "{user[blogUrl]} ({user[id]})",
                      "Direct Messages")
-    pattern = rf"{BASE_PATTERN}/app/messages/?\?dialogId=(\d+)"
+    pattern = BASE_PATTERN + r"/app/messages/?\?dialogId=(\d+)"
     example = "https://boosty.to/app/messages?dialogId=12345"
 
     def items(self):
@@ -424,7 +424,7 @@ class BoostyAPI():
             params["offset"] = offset
 
     def dialog(self, dialog_id):
-        endpoint = f"/v1/dialog/{dialog_id}"
+        endpoint = "/v1/dialog/" + dialog_id
         return self._call(endpoint)
 
     def dialog_messages(self, dialog_id, limit=300, offset=None):
diff --git a/gallery_dl/extractor/booth.py b/gallery_dl/extractor/booth.py
index 3c000b19..c232c588 100644
--- a/gallery_dl/extractor/booth.py
+++ b/gallery_dl/extractor/booth.py
@@ -116,7 +116,7 @@ class BoothShopExtractor(BoothExtractor):
         BoothExtractor.__init__(self, match)
 
     def shop_items(self):
-        return self._pagination(f"{self.root}/items")
+        return self._pagination(self.root + "/items")
 
 
 def _fallback(url):
diff --git a/gallery_dl/extractor/bunkr.py b/gallery_dl/extractor/bunkr.py
index ed9cd0f7..2c08f003 100644
--- a/gallery_dl/extractor/bunkr.py
+++ b/gallery_dl/extractor/bunkr.py
@@ -64,7 +64,7 @@ class BunkrAlbumExtractor(LolisafeAlbumExtractor):
     root_dl = "https://get.bunkrr.su"
     root_api = "https://apidl.bunkr.ru"
     archive_fmt = "{album_id}_{id|id_url|slug}"
-    pattern = rf"{BASE_PATTERN}/a/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/a/([^/?#]+)"
     example = "https://bunkr.si/a/ID"
 
     def __init__(self, match):
@@ -189,7 +189,7 @@ class BunkrAlbumExtractor(LolisafeAlbumExtractor):
                                  json={"id": data_id})
 
         if data.get("encrypted"):
-            key = f"SECRET_KEY_{data['timestamp'] // 3600}"
+            key = "SECRET_KEY_" + str(data["timestamp"] // 3600)
             file_url = util.decrypt_xor(data["url"], key.encode())
         else:
             file_url = data["url"]
@@ -216,12 +216,12 @@ class BunkrMediaExtractor(BunkrAlbumExtractor):
     """Extractor for bunkr.si media links"""
     subcategory = "media"
     directory_fmt = ("{category}",)
-    pattern = rf"{BASE_PATTERN}(/[fvid]/[^/?#]+)"
+    pattern = BASE_PATTERN + r"(/[fvid]/[^/?#]+)"
     example = "https://bunkr.si/f/FILENAME"
 
     def fetch_album(self, album_id):
         try:
-            page = self.request(f"{self.root}{album_id}").text
+            page = self.request(self.root + album_id).text
             data_id = text.extr(page, 'data-file-id="', '"')
             file = self._extract_file(data_id)
             file["name"] = text.unquote(text.unescape(text.extr(
diff --git a/gallery_dl/extractor/chevereto.py b/gallery_dl/extractor/chevereto.py
index 9a766d06..0b40fb93 100644
--- a/gallery_dl/extractor/chevereto.py
+++ b/gallery_dl/extractor/chevereto.py
@@ -60,7 +60,7 @@ BASE_PATTERN = CheveretoExtractor.update({
 class CheveretoImageExtractor(CheveretoExtractor):
     """Extractor for chevereto images"""
     subcategory = "image"
-    pattern = rf"{BASE_PATTERN}(/im(?:g|age)/[^/?#]+)"
+    pattern = BASE_PATTERN + r"(/im(?:g|age)/[^/?#]+)"
     example = "https://jpg7.cr/img/TITLE.ID"
 
     def items(self):
@@ -98,7 +98,7 @@ class CheveretoImageExtractor(CheveretoExtractor):
 class CheveretoVideoExtractor(CheveretoExtractor):
     """Extractor for chevereto videos"""
     subcategory = "video"
-    pattern = rf"{BASE_PATTERN}(/video/[^/?#]+)"
+    pattern = BASE_PATTERN + r"(/video/[^/?#]+)"
     example = "https://imagepond.net/video/TITLE.ID"
 
     def items(self):
@@ -145,7 +145,7 @@ class CheveretoVideoExtractor(CheveretoExtractor):
 class CheveretoAlbumExtractor(CheveretoExtractor):
     """Extractor for chevereto albums"""
     subcategory = "album"
-    pattern = rf"{BASE_PATTERN}(/a(?:lbum)?/[^/?#]+(?:/sub)?)"
+    pattern = BASE_PATTERN + r"(/a(?:lbum)?/[^/?#]+(?:/sub)?)"
     example = "https://jpg7.cr/album/TITLE.ID"
 
     def items(self):
@@ -182,7 +182,7 @@ class CheveretoAlbumExtractor(CheveretoExtractor):
 class CheveretoCategoryExtractor(CheveretoExtractor):
     """Extractor for chevereto galleries"""
     subcategory = "category"
-    pattern = rf"{BASE_PATTERN}(/category/[^/?#]+)"
+    pattern = BASE_PATTERN + r"(/category/[^/?#]+)"
     example = "https://imglike.com/category/TITLE"
 
     def items(self):
@@ -194,7 +194,7 @@ class CheveretoCategoryExtractor(CheveretoExtractor):
 class CheveretoUserExtractor(CheveretoExtractor):
     """Extractor for chevereto users"""
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}(/[^/?#]+(?:/albums)?)"
+    pattern = BASE_PATTERN + r"(/[^/?#]+(?:/albums)?)"
     example = "https://jpg7.cr/USER"
 
     def items(self):
diff --git a/gallery_dl/extractor/cien.py b/gallery_dl/extractor/cien.py
index c68af2e7..d7dab489 100644
--- a/gallery_dl/extractor/cien.py
+++ b/gallery_dl/extractor/cien.py
@@ -48,7 +48,7 @@ class CienArticleExtractor(CienExtractor):
     filename_fmt = "{num:>02} {filename}.{extension}"
     directory_fmt = ("{category}", "{author[name]}", "{post_id} {name}")
     archive_fmt = "{post_id}_{num}"
-    pattern = rf"{BASE_PATTERN}/creator/(\d+)/article/(\d+)"
+    pattern = BASE_PATTERN + r"/creator/(\d+)/article/(\d+)"
     example = "https://ci-en.net/creator/123/article/12345"
 
     def items(self):
@@ -160,7 +160,7 @@ class CienArticleExtractor(CienExtractor):
 
 class CienCreatorExtractor(CienExtractor):
     subcategory = "creator"
-    pattern = rf"{BASE_PATTERN}/creator/(\d+)(?:/article(?:\?([^#]+))?)?/?$"
+    pattern = BASE_PATTERN + r"/creator/(\d+)(?:/article(?:\?([^#]+))?)?/?$"
     example = "https://ci-en.net/creator/123"
 
     def items(self):
@@ -172,7 +172,7 @@ class CienCreatorExtractor(CienExtractor):
 
 class CienRecentExtractor(CienExtractor):
     subcategory = "recent"
-    pattern = rf"{BASE_PATTERN}/mypage/recent(?:\?([^#]+))?"
+    pattern = BASE_PATTERN + r"/mypage/recent(?:\?([^#]+))?"
     example = "https://ci-en.net/mypage/recent"
 
     def items(self):
@@ -183,7 +183,7 @@ class CienRecentExtractor(CienExtractor):
 
 class CienFollowingExtractor(CienExtractor):
     subcategory = "following"
-    pattern = rf"{BASE_PATTERN}/mypage/subscription(/following)?"
+    pattern = BASE_PATTERN + r"/mypage/subscription(/following)?"
     example = "https://ci-en.net/mypage/subscription"
 
     def items(self):
diff --git a/gallery_dl/extractor/civitai.py b/gallery_dl/extractor/civitai.py
index 742c561a..708f9595 100644
--- a/gallery_dl/extractor/civitai.py
+++ b/gallery_dl/extractor/civitai.py
@@ -15,7 +15,7 @@ import itertools
 import time
 
 BASE_PATTERN = r"(?:https?://)?civitai\.com"
-USER_PATTERN = rf"{BASE_PATTERN}/user/([^/?#]+)"
+USER_PATTERN = BASE_PATTERN + r"/user/([^/?#]+)"
 
 
 class CivitaiExtractor(Extractor):
@@ -258,7 +258,7 @@ class CivitaiModelExtractor(CivitaiExtractor):
     directory_fmt = ("{category}", "{user[username]}",
                      "{model[id]}{model[name]:? //}",
                      "{version[id]}{version[name]:? //}")
-    pattern = rf"{BASE_PATTERN}/models/(\d+)(?:/?\?modelVersionId=(\d+))?"
+    pattern = BASE_PATTERN + r"/models/(\d+)(?:/?\?modelVersionId=(\d+))?"
     example = "https://civitai.com/models/12345/TITLE"
 
     def items(self):
@@ -375,7 +375,7 @@ class CivitaiModelExtractor(CivitaiExtractor):
 
 class CivitaiImageExtractor(CivitaiExtractor):
     subcategory = "image"
-    pattern = rf"{BASE_PATTERN}/images/(\d+)"
+    pattern = BASE_PATTERN + r"/images/(\d+)"
     example = "https://civitai.com/images/12345"
 
     def images(self):
@@ -386,7 +386,7 @@ class CivitaiCollectionExtractor(CivitaiExtractor):
     subcategory = "collection"
     directory_fmt = ("{category}", "{user_collection[username]}",
                      "collections", "{collection[id]}{collection[name]:? //}")
-    pattern = rf"{BASE_PATTERN}/collections/(\d+)"
+    pattern = BASE_PATTERN + r"/collections/(\d+)"
     example = "https://civitai.com/collections/12345"
 
     def images(self):
@@ -408,7 +408,7 @@ class CivitaiPostExtractor(CivitaiExtractor):
     subcategory = "post"
     directory_fmt = ("{category}", "{username|user[username]}", "posts",
                      "{post[id]}{post[title]:? //}")
-    pattern = rf"{BASE_PATTERN}/posts/(\d+)"
+    pattern = BASE_PATTERN + r"/posts/(\d+)"
     example = "https://civitai.com/posts/12345"
 
     def posts(self):
@@ -417,7 +417,7 @@ class CivitaiPostExtractor(CivitaiExtractor):
 
 class CivitaiTagExtractor(CivitaiExtractor):
     subcategory = "tag"
-    pattern = rf"{BASE_PATTERN}/tag/([^/?&#]+)"
+    pattern = BASE_PATTERN + r"/tag/([^/?&#]+)"
     example = "https://civitai.com/tag/TAG"
 
     def models(self):
@@ -427,7 +427,7 @@ class CivitaiTagExtractor(CivitaiExtractor):
 
 class CivitaiSearchModelsExtractor(CivitaiExtractor):
     subcategory = "search-models"
-    pattern = rf"{BASE_PATTERN}/search/models\?([^#]+)"
+    pattern = BASE_PATTERN + r"/search/models\?([^#]+)"
     example = "https://civitai.com/search/models?query=QUERY"
 
     def models(self):
@@ -438,7 +438,7 @@ class CivitaiSearchModelsExtractor(CivitaiExtractor):
 
 class CivitaiSearchImagesExtractor(CivitaiExtractor):
     subcategory = "search-images"
-    pattern = rf"{BASE_PATTERN}/search/images\?([^#]+)"
+    pattern = BASE_PATTERN + r"/search/images\?([^#]+)"
     example = "https://civitai.com/search/images?query=QUERY"
 
     def images(self):
@@ -449,7 +449,7 @@ class CivitaiSearchImagesExtractor(CivitaiExtractor):
 
 class CivitaiModelsExtractor(CivitaiExtractor):
     subcategory = "models"
-    pattern = rf"{BASE_PATTERN}/models(?:/?\?([^#]+))?(?:$|#)"
+    pattern = BASE_PATTERN + r"/models(?:/?\?([^#]+))?(?:$|#)"
     example = "https://civitai.com/models"
 
     def models(self):
@@ -459,7 +459,7 @@ class CivitaiModelsExtractor(CivitaiExtractor):
 
 class CivitaiImagesExtractor(CivitaiExtractor):
     subcategory = "images"
-    pattern = rf"{BASE_PATTERN}/images(?:/?\?([^#]+))?(?:$|#)"
+    pattern = BASE_PATTERN + r"/images(?:/?\?([^#]+))?(?:$|#)"
     example = "https://civitai.com/images"
 
     def images(self):
@@ -470,7 +470,7 @@ class CivitaiImagesExtractor(CivitaiExtractor):
 
 class CivitaiVideosExtractor(CivitaiExtractor):
     subcategory = "videos"
-    pattern = rf"{BASE_PATTERN}/videos(?:/?\?([^#]+))?(?:$|#)"
+    pattern = BASE_PATTERN + r"/videos(?:/?\?([^#]+))?(?:$|#)"
     example = "https://civitai.com/videos"
 
     def images(self):
@@ -481,7 +481,7 @@ class CivitaiVideosExtractor(CivitaiExtractor):
 
 class CivitaiPostsExtractor(CivitaiExtractor):
     subcategory = "posts"
-    pattern = rf"{BASE_PATTERN}/posts(?:/?\?([^#]+))?(?:$|#)"
+    pattern = BASE_PATTERN + r"/posts(?:/?\?([^#]+))?(?:$|#)"
     example = "https://civitai.com/posts"
 
     def posts(self):
@@ -490,7 +490,7 @@ class CivitaiPostsExtractor(CivitaiExtractor):
 
 
 class CivitaiUserExtractor(Dispatch, CivitaiExtractor):
-    pattern = rf"{USER_PATTERN}/?(?:$|\?|#)"
+    pattern = USER_PATTERN + r"/?(?:$|\?|#)"
     example = "https://civitai.com/user/USER"
 
     def items(self):
@@ -506,7 +506,7 @@ class CivitaiUserExtractor(Dispatch, CivitaiExtractor):
 
 class CivitaiUserModelsExtractor(CivitaiExtractor):
     subcategory = "user-models"
-    pattern = rf"{USER_PATTERN}/models/?(?:\?([^#]+))?"
+    pattern = USER_PATTERN + r"/models/?(?:\?([^#]+))?"
     example = "https://civitai.com/user/USER/models"
 
     def models(self):
@@ -520,7 +520,7 @@ class CivitaiUserPostsExtractor(CivitaiExtractor):
     subcategory = "user-posts"
     directory_fmt = ("{category}", "{username|user[username]}", "posts",
                      "{post[id]}{post[title]:? //}")
-    pattern = rf"{USER_PATTERN}/posts/?(?:\?([^#]+))?"
+    pattern = USER_PATTERN + r"/posts/?(?:\?([^#]+))?"
     example = "https://civitai.com/user/USER/posts"
 
     def posts(self):
@@ -532,7 +532,7 @@ class CivitaiUserPostsExtractor(CivitaiExtractor):
 
 class CivitaiUserImagesExtractor(CivitaiExtractor):
     subcategory = "user-images"
-    pattern = rf"{USER_PATTERN}/images/?(?:\?([^#]+))?"
+    pattern = USER_PATTERN + r"/images/?(?:\?([^#]+))?"
     example = "https://civitai.com/user/USER/images"
 
     def __init__(self, match):
@@ -553,7 +553,7 @@ class CivitaiUserImagesExtractor(CivitaiExtractor):
 class CivitaiUserVideosExtractor(CivitaiExtractor):
     subcategory = "user-videos"
     directory_fmt = ("{category}", "{username|user[username]}", "videos")
-    pattern = rf"{USER_PATTERN}/videos/?(?:\?([^#]+))?"
+    pattern = USER_PATTERN + r"/videos/?(?:\?([^#]+))?"
     example = "https://civitai.com/user/USER/videos"
 
     def __init__(self, match):
@@ -572,7 +572,7 @@ class CivitaiUserVideosExtractor(CivitaiExtractor):
 
 class CivitaiUserCollectionsExtractor(CivitaiExtractor):
     subcategory = "user-collections"
-    pattern = rf"{USER_PATTERN}/collections/?(?:\?([^#]+))?"
+    pattern = USER_PATTERN + r"/collections/?(?:\?([^#]+))?"
     example = "https://civitai.com/user/USER/collections"
 
     def items(self):
@@ -580,10 +580,10 @@ class CivitaiUserCollectionsExtractor(CivitaiExtractor):
         params = self._parse_query(query)
         params["userId"] = self.api.user(text.unquote(user))[0]["id"]
 
-        base = f"{self.root}/collections/"
+        base = self.root + "/collections/"
         for collection in self.api.collections(params):
             collection["_extractor"] = CivitaiCollectionExtractor
-            yield Message.Queue, f"{base}{collection['id']}", collection
+            yield Message.Queue, base + str(collection["id"]), collection
 
 
 class CivitaiGeneratedExtractor(CivitaiExtractor):
@@ -591,7 +591,7 @@ class CivitaiGeneratedExtractor(CivitaiExtractor):
     subcategory = "generated"
     filename_fmt = "{filename}.{extension}"
     directory_fmt = ("{category}", "generated")
-    pattern = rf"{BASE_PATTERN}/generate"
+    pattern = BASE_PATTERN + "/generate"
     example = "https://civitai.com/generate"
 
     def items(self):
@@ -647,12 +647,12 @@ class CivitaiRestAPI():
         })
 
     def model(self, model_id):
-        endpoint = f"/v1/models/{model_id}"
+        endpoint = "/v1/models/" + str(model_id)
         return self._call(endpoint)
 
     @memcache(keyarg=1)
     def model_version(self, model_version_id):
-        endpoint = f"/v1/model-versions/{model_version_id}"
+        endpoint = "/v1/model-versions/" + str(model_version_id)
         return self._call(endpoint)
 
     def models(self, params):
@@ -945,7 +945,7 @@ class CivitaiSearchAPI():
 
         if auth := extractor.config("token"):
             if " " not in auth:
-                auth = f"Bearer {auth}"
+                auth = "Bearer " + auth
         else:
             auth = ("Bearer 8c46eb2508e21db1e9828a97968d"
                     "91ab1ca1caa5f70a00e88a2ba1e286603b61")
diff --git a/gallery_dl/extractor/comick.py b/gallery_dl/extractor/comick.py
index 98167866..c119b2e3 100644
--- a/gallery_dl/extractor/comick.py
+++ b/gallery_dl/extractor/comick.py
@@ -27,7 +27,7 @@ class ComickCoversExtractor(ComickBase, GalleryExtractor):
     directory_fmt = ("{category}", "{manga}", "Covers")
     filename_fmt = "{volume:>02}_{lang}.{extension}"
     archive_fmt = "c_{id}"
-    pattern = rf"{BASE_PATTERN}/comic/([\w-]+)/cover"
+    pattern = BASE_PATTERN + r"/comic/([\w-]+)/cover"
     example = "https://comick.io/comic/MANGA/cover"
 
     def metadata(self, page):
@@ -44,7 +44,7 @@ class ComickCoversExtractor(ComickBase, GalleryExtractor):
         covers.reverse()
 
         return [
-            (f"https://meo.comick.pictures/{cover['b2key']}", {
+            ("https://meo.comick.pictures/" + cover["b2key"], {
                 "id"    : cover["id"],
                 "width" : cover["w"],
                 "height": cover["h"],
@@ -60,7 +60,7 @@ class ComickCoversExtractor(ComickBase, GalleryExtractor):
 class ComickChapterExtractor(ComickBase, ChapterExtractor):
     """Extractor for comick.io manga chapters"""
     archive_fmt = "{chapter_hid}_{page}"
-    pattern = (rf"{BASE_PATTERN}/comic/([\w-]+)"
+    pattern = (BASE_PATTERN + r"/comic/([\w-]+)"
                r"/(\w+(?:-(?:chapter|volume)-[^/?#]+)?)")
     example = "https://comick.io/comic/MANGA/ID-chapter-123-en"
 
@@ -128,7 +128,7 @@ class ComickChapterExtractor(ComickBase, ChapterExtractor):
             return ()
 
         return [
-            (f"https://meo.comick.pictures/{img['b2key']}", {
+            ("https://meo.comick.pictures/" + img["b2key"], {
                 "width"    : img["w"],
                 "height"   : img["h"],
                 "size"     : img["s"],
@@ -140,7 +140,7 @@ class ComickChapterExtractor(ComickBase, ChapterExtractor):
 
 class ComickMangaExtractor(ComickBase, MangaExtractor):
     """Extractor for comick.io manga"""
-    pattern = rf"{BASE_PATTERN}/comic/([\w-]+)/?(?:\?([^#]+))?"
+    pattern = BASE_PATTERN + r"/comic/([\w-]+)/?(?:\?([^#]+))?"
     example = "https://comick.io/comic/MANGA"
 
     def items(self):
diff --git a/gallery_dl/extractor/common.py b/gallery_dl/extractor/common.py
index 13c7bbef..a6379a3e 100644
--- a/gallery_dl/extractor/common.py
+++ b/gallery_dl/extractor/common.py
@@ -766,7 +766,7 @@ class GalleryExtractor(Extractor):
         Extractor.__init__(self, match)
 
         if url is None and (path := self.groups[0]) and path[0] == "/":
-            self.page_url = f"{self.root}{path}"
+            self.page_url = self.root + path
         else:
             self.page_url = url
 
@@ -863,7 +863,7 @@ class MangaExtractor(Extractor):
         Extractor.__init__(self, match)
 
         if url is None and (path := self.groups[0]) and path[0] == "/":
-            self.page_url = f"{self.root}{path}"
+            self.page_url = self.root + path
         else:
             self.page_url = url
 
diff --git a/gallery_dl/extractor/cyberdrop.py b/gallery_dl/extractor/cyberdrop.py
index 93d3953d..a2cb0caa 100644
--- a/gallery_dl/extractor/cyberdrop.py
+++ b/gallery_dl/extractor/cyberdrop.py
@@ -18,7 +18,7 @@ class CyberdropAlbumExtractor(lolisafe.LolisafeAlbumExtractor):
     category = "cyberdrop"
     root = "https://cyberdrop.cr"
     root_api = "https://api.cyberdrop.cr"
-    pattern = rf"{BASE_PATTERN}/a/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/a/([^/?#]+)"
     example = "https://cyberdrop.cr/a/ID"
 
     def items(self):
@@ -76,7 +76,7 @@ class CyberdropMediaExtractor(CyberdropAlbumExtractor):
     """Extractor for cyberdrop media links"""
     subcategory = "media"
     directory_fmt = ("{category}",)
-    pattern = rf"{BASE_PATTERN}/f/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/f/([^/?#]+)"
     example = "https://cyberdrop.cr/f/ID"
 
     def fetch_album(self, album_id):
diff --git a/gallery_dl/extractor/cyberfile.py b/gallery_dl/extractor/cyberfile.py
index e8c0061f..49cc6db1 100644
--- a/gallery_dl/extractor/cyberfile.py
+++ b/gallery_dl/extractor/cyberfile.py
@@ -20,7 +20,7 @@ class CyberfileExtractor(Extractor):
     root = "https://cyberfile.me"
 
     def request_api(self, endpoint, data):
-        url = f"{self.root}{endpoint}"
+        url = self.root + endpoint
         headers = {
             "X-Requested-With": "XMLHttpRequest",
             "Origin": self.root,
@@ -29,7 +29,7 @@ class CyberfileExtractor(Extractor):
             url, method="POST", headers=headers, data=data)
 
         if "albumPasswordModel" in resp.get("javascript", ""):
-            url_pw = f"{self.root}/ajax/folder_password_process"
+            url_pw = self.root + "/ajax/folder_password_process"
             data_pw = {
                 "folderPassword": self._get_auth_info(password=True)[1],
                 "folderId": text.extr(
@@ -48,7 +48,7 @@ class CyberfileExtractor(Extractor):
 
 class CyberfileFolderExtractor(CyberfileExtractor):
     subcategory = "folder"
-    pattern = rf"{BASE_PATTERN}/folder/([0-9a-f]+)"
+    pattern = BASE_PATTERN + r"/folder/([0-9a-f]+)"
     example = "https://cyberfile.me/folder/0123456789abcdef/NAME"
 
     def items(self):
@@ -97,7 +97,7 @@ class CyberfileFolderExtractor(CyberfileExtractor):
 
 class CyberfileSharedExtractor(CyberfileExtractor):
     subcategory = "shared"
-    pattern = rf"{BASE_PATTERN}/shared/([a-zA-Z0-9]+)"
+    pattern = BASE_PATTERN + r"/shared/([a-zA-Z0-9]+)"
     example = "https://cyberfile.me/shared/AbCdEfGhIjK"
 
     def items(self):
@@ -129,7 +129,7 @@ class CyberfileSharedExtractor(CyberfileExtractor):
 class CyberfileFileExtractor(CyberfileExtractor):
     subcategory = "file"
     directory_fmt = ("{category}", "{uploader}", "{folder}")
-    pattern = rf"{BASE_PATTERN}/([a-zA-Z0-9]+)"
+    pattern = BASE_PATTERN + r"/([a-zA-Z0-9]+)"
     example = "https://cyberfile.me/AbCdE"
 
     def items(self):
diff --git a/gallery_dl/extractor/danbooru.py b/gallery_dl/extractor/danbooru.py
index 5ea33c4c..588d94b5 100644
--- a/gallery_dl/extractor/danbooru.py
+++ b/gallery_dl/extractor/danbooru.py
@@ -155,7 +155,7 @@ class DanbooruExtractor(BaseExtractor):
                 return
 
             if prefix:
-                params["page"] = f"{prefix}{posts[-1]['id']}"
+                params["page"] = prefix + str(posts[-1]["id"])
             elif params["page"]:
                 params["page"] += 1
             else:
@@ -174,9 +174,8 @@ class DanbooruExtractor(BaseExtractor):
         else:
             ext = data["ZIP:ZipFileName"].rpartition(".")[2]
 
-        fmt = ("{:>06}." + ext).format
         delays = data["Ugoira:FrameDelays"]
-        return [{"file": fmt(index), "delay": delay}
+        return [{"file": f"{index:>06}.{ext}", "delay": delay}
                 for index, delay in enumerate(delays)]
 
     def _collection_posts(self, cid, ctype):
@@ -251,7 +250,7 @@ class DanbooruTagExtractor(DanbooruExtractor):
     subcategory = "tag"
     directory_fmt = ("{category}", "{search_tags}")
     archive_fmt = "t_{search_tags}_{id}"
-    pattern = rf"{BASE_PATTERN}/posts\?(?:[^&#]*&)*tags=([^&#]*)"
+    pattern = BASE_PATTERN + r"/posts\?(?:[^&#]*&)*tags=([^&#]*)"
     example = "https://danbooru.donmai.us/posts?tags=TAG"
 
     def metadata(self):
@@ -279,7 +278,7 @@ class DanbooruTagExtractor(DanbooruExtractor):
 class DanbooruRandomExtractor(DanbooruTagExtractor):
     """Extractor for a random danbooru post"""
     subcategory = "random"
-    pattern = rf"{BASE_PATTERN}/posts/random(?:\?(?:[^&#]*&)*tags=([^&#]*))?"
+    pattern = BASE_PATTERN + r"/posts/random(?:\?(?:[^&#]*&)*tags=([^&#]*))?"
     example = "https://danbooru.donmai.us/posts/random?tags=TAG"
 
     def metadata(self):
@@ -299,7 +298,7 @@ class DanbooruPoolExtractor(DanbooruExtractor):
     directory_fmt = ("{category}", "pool", "{pool[id]} {pool[name]}")
     filename_fmt = "{num:>04}_{id}_{filename}.{extension}"
     archive_fmt = "p_{pool[id]}_{id}"
-    pattern = rf"{BASE_PATTERN}/pool(?:s|/show)/(\d+)"
+    pattern = BASE_PATTERN + r"/pool(?:s|/show)/(\d+)"
     example = "https://danbooru.donmai.us/pools/12345"
 
     def metadata(self):
@@ -317,7 +316,7 @@ class DanbooruFavgroupExtractor(DanbooruExtractor):
                      "{favgroup[id]} {favgroup[name]}")
     filename_fmt = "{num:>04}_{id}_{filename}.{extension}"
     archive_fmt = "fg_{favgroup[id]}_{id}"
-    pattern = rf"{BASE_PATTERN}/favorite_group(?:s|/show)/(\d+)"
+    pattern = BASE_PATTERN + r"/favorite_group(?:s|/show)/(\d+)"
     example = "https://danbooru.donmai.us/favorite_groups/12345"
 
     def metadata(self):
@@ -332,7 +331,7 @@ class DanbooruPostExtractor(DanbooruExtractor):
     """Extractor for single danbooru posts"""
     subcategory = "post"
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}/post(?:s|/show)/(\d+)"
+    pattern = BASE_PATTERN + r"/post(?:s|/show)/(\d+)"
     example = "https://danbooru.donmai.us/posts/12345"
 
     def posts(self):
@@ -349,7 +348,7 @@ class DanbooruMediaassetExtractor(DanbooruExtractor):
     subcategory = "media-asset"
     filename_fmt = "{category}_ma{id}_{filename}.{extension}"
     archive_fmt = "m{id}"
-    pattern = rf"{BASE_PATTERN}/media_assets/(\d+)"
+    pattern = BASE_PATTERN + r"/media_assets/(\d+)"
     example = "https://danbooru.donmai.us/media_assets/12345"
 
     def posts(self):
@@ -375,7 +374,7 @@ class DanbooruPopularExtractor(DanbooruExtractor):
     subcategory = "popular"
     directory_fmt = ("{category}", "popular", "{scale}", "{date}")
     archive_fmt = "P_{scale[0]}_{date}_{id}"
-    pattern = rf"{BASE_PATTERN}/(?:explore/posts/)?popular(?:\?([^#]*))?"
+    pattern = BASE_PATTERN + r"/(?:explore/posts/)?popular(?:\?([^#]*))?"
     example = "https://danbooru.donmai.us/explore/posts/popular"
 
     def metadata(self):
@@ -398,7 +397,7 @@ class DanbooruPopularExtractor(DanbooruExtractor):
 class DanbooruArtistExtractor(DanbooruExtractor):
     """Extractor for danbooru artists"""
     subcategory = "artist"
-    pattern = rf"{BASE_PATTERN}/artists/(\d+)"
+    pattern = BASE_PATTERN + r"/artists/(\d+)"
     example = "https://danbooru.donmai.us/artists/12345"
 
     items = DanbooruExtractor.items_artists
@@ -411,7 +410,7 @@ class DanbooruArtistExtractor(DanbooruExtractor):
 class DanbooruArtistSearchExtractor(DanbooruExtractor):
     """Extractor for danbooru artist searches"""
     subcategory = "artist-search"
-    pattern = rf"{BASE_PATTERN}/artists/?\?([^#]+)"
+    pattern = BASE_PATTERN + r"/artists/?\?([^#]+)"
     example = "https://danbooru.donmai.us/artists?QUERY"
 
     items = DanbooruExtractor.items_artists
diff --git a/gallery_dl/extractor/dandadan.py b/gallery_dl/extractor/dandadan.py
index 48dc0b7c..9349d5fe 100644
--- a/gallery_dl/extractor/dandadan.py
+++ b/gallery_dl/extractor/dandadan.py
@@ -22,7 +22,7 @@ class DandadanBase():
 
 class DandadanChapterExtractor(DandadanBase, ChapterExtractor):
     """Extractor for dandadan manga chapters"""
-    pattern = rf"{BASE_PATTERN}(/manga/dandadan-chapter-([^/?#]+)/?)"
+    pattern = BASE_PATTERN + r"(/manga/dandadan-chapter-([^/?#]+)/?)"
     example = "https://dandadan.net/manga/dandadan-chapter-123/"
 
     def metadata(self, page):
@@ -31,7 +31,7 @@ class DandadanChapterExtractor(DandadanBase, ChapterExtractor):
         return {
             "manga"        : "Dandadan",
             "chapter"      : text.parse_int(chapter),
-            "chapter_minor": f"{sep}{minor}",
+            "chapter_minor": sep + minor,
             "lang"         : "en",
         }
 
@@ -54,7 +54,7 @@ class DandadanChapterExtractor(DandadanBase, ChapterExtractor):
 class DandadanMangaExtractor(DandadanBase, MangaExtractor):
     """Extractor for dandadan manga"""
     chapterclass = DandadanChapterExtractor
-    pattern = rf"{BASE_PATTERN}(/)"
+    pattern = BASE_PATTERN + r"(/)"
     example = "https://dandadan.net/"
 
     def chapters(self, page):
diff --git a/gallery_dl/extractor/dankefuerslesen.py b/gallery_dl/extractor/dankefuerslesen.py
index ed7e40bb..baebb6f3 100644
--- a/gallery_dl/extractor/dankefuerslesen.py
+++ b/gallery_dl/extractor/dankefuerslesen.py
@@ -28,13 +28,13 @@ class DankefuerslesenBase():
 
 class DankefuerslesenChapterExtractor(DankefuerslesenBase, ChapterExtractor):
     """Extractor for Danke fürs Lesen manga chapters"""
-    pattern = rf"{BASE_PATTERN}/read/manga/([\w-]+)/([\w-]+)"
+    pattern = BASE_PATTERN + r"/read/manga/([\w-]+)/([\w-]+)"
     example = "https://danke.moe/read/manga/TITLE/123/1/"
 
     def _init(self):
         self.zip = self.config("zip", False)
         if self.zip:
-            self.filename_fmt = f"{self.directory_fmt[-1]}.{{extension}}"
+            self.filename_fmt = self.directory_fmt[-1] + ".{extension}"
             self.directory_fmt = self.directory_fmt[:-1]
 
     def metadata(self, page):
@@ -95,7 +95,7 @@ class DankefuerslesenMangaExtractor(DankefuerslesenBase, MangaExtractor):
     """Extractor for Danke fürs Lesen manga"""
     chapterclass = DankefuerslesenChapterExtractor
     reverse = False
-    pattern = rf"{BASE_PATTERN}/read/manga/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/read/manga/([^/?#]+)"
     example = "https://danke.moe/read/manga/TITLE/"
 
     def chapters(self, page):
diff --git a/gallery_dl/extractor/desktopography.py b/gallery_dl/extractor/desktopography.py
index be250539..816816a8 100644
--- a/gallery_dl/extractor/desktopography.py
+++ b/gallery_dl/extractor/desktopography.py
@@ -22,7 +22,7 @@ class DesktopographyExtractor(Extractor):
 class DesktopographySiteExtractor(DesktopographyExtractor):
     """Extractor for all desktopography exhibitions """
     subcategory = "site"
-    pattern = rf"{BASE_PATTERN}/$"
+    pattern = BASE_PATTERN + r"/$"
     example = "https://desktopography.net/"
 
     def items(self):
@@ -41,7 +41,7 @@ class DesktopographySiteExtractor(DesktopographyExtractor):
 class DesktopographyExhibitionExtractor(DesktopographyExtractor):
     """Extractor for a yearly desktopography exhibition"""
     subcategory = "exhibition"
-    pattern = rf"{BASE_PATTERN}/exhibition-([^/?#]+)/"
+    pattern = BASE_PATTERN + r"/exhibition-([^/?#]+)/"
     example = "https://desktopography.net/exhibition-2020/"
 
     def __init__(self, match):
@@ -70,7 +70,7 @@ class DesktopographyExhibitionExtractor(DesktopographyExtractor):
 class DesktopographyEntryExtractor(DesktopographyExtractor):
     """Extractor for all resolutions of a desktopography wallpaper"""
     subcategory = "entry"
-    pattern = rf"{BASE_PATTERN}/portfolios/([\w-]+)"
+    pattern = BASE_PATTERN + r"/portfolios/([\w-]+)"
     example = "https://desktopography.net/portfolios/NAME/"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/deviantart.py b/gallery_dl/extractor/deviantart.py
index 5bd43d4b..0769c7ae 100644
--- a/gallery_dl/extractor/deviantart.py
+++ b/gallery_dl/extractor/deviantart.py
@@ -66,7 +66,7 @@ class DeviantartExtractor(Extractor):
                 self.quality = "-fullview.png?"
                 self.quality_sub = text.re(r"-fullview\.[a-z0-9]+\?").sub
             else:
-                self.quality = f",q_{self.quality}"
+                self.quality = ",q_" + str(self.quality)
                 self.quality_sub = text.re(r",q_\d+").sub
 
         if self.intermediary:
@@ -864,7 +864,7 @@ x2="45.4107524%" y2="71.4898596%" id="app-root-3">\
 
 class DeviantartUserExtractor(Dispatch, DeviantartExtractor):
     """Extractor for an artist's user profile"""
-    pattern = rf"{BASE_PATTERN}/?$"
+    pattern = BASE_PATTERN + r"/?$"
     example = "https://www.deviantart.com/USER"
 
     def items(self):
@@ -887,7 +887,7 @@ class DeviantartGalleryExtractor(DeviantartExtractor):
     """Extractor for all deviations from an artist's gallery"""
     subcategory = "gallery"
     archive_fmt = "g_{_username}_{index}.{extension}"
-    pattern = (rf"{BASE_PATTERN}/gallery"
+    pattern = (BASE_PATTERN + r"/gallery"
                r"(?:/all|/recommended-for-you)?/?(\?(?!q=).*)?$")
     example = "https://www.deviantart.com/USER/gallery/"
 
@@ -902,7 +902,7 @@ class DeviantartAvatarExtractor(DeviantartExtractor):
     """Extractor for an artist's avatar"""
     subcategory = "avatar"
     archive_fmt = "a_{_username}_{index}"
-    pattern = rf"{BASE_PATTERN}/avatar"
+    pattern = BASE_PATTERN + r"/avatar"
     example = "https://www.deviantart.com/USER/avatar/"
 
     def deviations(self):
@@ -956,7 +956,7 @@ class DeviantartBackgroundExtractor(DeviantartExtractor):
     """Extractor for an artist's banner"""
     subcategory = "background"
     archive_fmt = "b_{index}"
-    pattern = rf"{BASE_PATTERN}/ba(?:nner|ckground)"
+    pattern = BASE_PATTERN + r"/ba(?:nner|ckground)"
     example = "https://www.deviantart.com/USER/banner/"
 
     def deviations(self):
@@ -972,7 +972,7 @@ class DeviantartFolderExtractor(DeviantartExtractor):
     subcategory = "folder"
     directory_fmt = ("{category}", "{username}", "{folder[title]}")
     archive_fmt = "F_{folder[uuid]}_{index}.{extension}"
-    pattern = rf"{BASE_PATTERN}/gallery/([^/?#]+)/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/gallery/([^/?#]+)/([^/?#]+)"
     example = "https://www.deviantart.com/USER/gallery/12345/TITLE"
 
     def __init__(self, match):
@@ -1088,7 +1088,7 @@ class DeviantartFavoriteExtractor(DeviantartExtractor):
     subcategory = "favorite"
     directory_fmt = ("{category}", "{username}", "Favourites")
     archive_fmt = "f_{_username}_{index}.{extension}"
-    pattern = rf"{BASE_PATTERN}/favourites(?:/all|/?\?catpath=)?/?$"
+    pattern = BASE_PATTERN + r"/favourites(?:/all|/?\?catpath=)?/?$"
     example = "https://www.deviantart.com/USER/favourites/"
 
     def deviations(self):
@@ -1105,7 +1105,7 @@ class DeviantartCollectionExtractor(DeviantartExtractor):
     directory_fmt = ("{category}", "{username}", "Favourites",
                      "{collection[title]}")
     archive_fmt = "C_{collection[uuid]}_{index}.{extension}"
-    pattern = rf"{BASE_PATTERN}/favourites/([^/?#]+)/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/favourites/([^/?#]+)/([^/?#]+)"
     example = "https://www.deviantart.com/USER/favourites/12345/TITLE"
 
     def __init__(self, match):
@@ -1136,7 +1136,7 @@ class DeviantartJournalExtractor(DeviantartExtractor):
     subcategory = "journal"
     directory_fmt = ("{category}", "{username}", "Journal")
     archive_fmt = "j_{_username}_{index}.{extension}"
-    pattern = rf"{BASE_PATTERN}/(?:posts(?:/journals)?|journal)/?(?:\?.*)?$"
+    pattern = BASE_PATTERN + r"/(?:posts(?:/journals)?|journal)/?(?:\?.*)?$"
     example = "https://www.deviantart.com/USER/posts/journals/"
 
     def deviations(self):
@@ -1149,7 +1149,7 @@ class DeviantartStatusExtractor(DeviantartExtractor):
     directory_fmt = ("{category}", "{username}", "Status")
     filename_fmt = "{category}_{index}_{title}_{date}.{extension}"
     archive_fmt = "S_{_username}_{index}.{extension}"
-    pattern = rf"{BASE_PATTERN}/posts/statuses"
+    pattern = BASE_PATTERN + r"/posts/statuses"
     example = "https://www.deviantart.com/USER/posts/statuses/"
 
     def deviations(self):
@@ -1253,7 +1253,7 @@ class DeviantartDeviationExtractor(DeviantartExtractor):
     """Extractor for single deviations"""
     subcategory = "deviation"
     archive_fmt = "g_{_username}_{index}.{extension}"
-    pattern = (rf"{BASE_PATTERN}/(art|journal)/(?:[^/?#]+-)?(\d+)"
+    pattern = (BASE_PATTERN + r"/(art|journal)/(?:[^/?#]+-)?(\d+)"
                r"|(?:https?://)?(?:www\.)?(?:fx)?deviantart\.com/"
                r"(?:view/|deviation/|view(?:-full)?\.php/*\?(?:[^#]+&)?id=)"
                r"(\d+)"  # bare deviation ID without slug
@@ -1315,7 +1315,7 @@ class DeviantartScrapsExtractor(DeviantartExtractor):
     subcategory = "scraps"
     directory_fmt = ("{category}", "{username}", "Scraps")
     archive_fmt = "s_{_username}_{index}.{extension}"
-    pattern = rf"{BASE_PATTERN}/gallery/(?:\?catpath=)?scraps\b"
+    pattern = BASE_PATTERN + r"/gallery/(?:\?catpath=)?scraps\b"
     example = "https://www.deviantart.com/USER/gallery/scraps"
 
     def deviations(self):
@@ -1382,7 +1382,7 @@ class DeviantartGallerySearchExtractor(DeviantartExtractor):
     """Extractor for deviantart gallery searches"""
     subcategory = "gallery-search"
     archive_fmt = "g_{_username}_{index}.{extension}"
-    pattern = rf"{BASE_PATTERN}/gallery/?\?(q=[^#]+)"
+    pattern = BASE_PATTERN + r"/gallery/?\?(q=[^#]+)"
     example = "https://www.deviantart.com/USER/gallery?q=QUERY"
 
     def __init__(self, match):
@@ -1412,7 +1412,7 @@ class DeviantartGallerySearchExtractor(DeviantartExtractor):
 class DeviantartFollowingExtractor(DeviantartExtractor):
     """Extractor for user's watched users"""
     subcategory = "following"
-    pattern = rf"{BASE_PATTERN}/(?:about#)?watching"
+    pattern = BASE_PATTERN + "/(?:about#)?watching"
     example = "https://www.deviantart.com/USER/about#watching"
 
     def items(self):
diff --git a/gallery_dl/extractor/discord.py b/gallery_dl/extractor/discord.py
index 0e7f3093..54cc433e 100644
--- a/gallery_dl/extractor/discord.py
+++ b/gallery_dl/extractor/discord.py
@@ -238,7 +238,7 @@ class DiscordExtractor(Extractor):
 
 class DiscordChannelExtractor(DiscordExtractor):
     subcategory = "channel"
-    pattern = rf"{BASE_PATTERN}/channels/(\d+)/(?:\d+/threads/)?(\d+)/?$"
+    pattern = BASE_PATTERN + r"/channels/(\d+)/(?:\d+/threads/)?(\d+)/?$"
     example = "https://discord.com/channels/1234567890/9876543210"
 
     def items(self):
@@ -251,7 +251,7 @@ class DiscordChannelExtractor(DiscordExtractor):
 
 class DiscordMessageExtractor(DiscordExtractor):
     subcategory = "message"
-    pattern = rf"{BASE_PATTERN}/channels/(\d+)/(\d+)/(\d+)/?$"
+    pattern = BASE_PATTERN + r"/channels/(\d+)/(\d+)/(\d+)/?$"
     example = "https://discord.com/channels/1234567890/9876543210/2468013579"
 
     def items(self):
@@ -268,7 +268,7 @@ class DiscordMessageExtractor(DiscordExtractor):
 
 class DiscordServerExtractor(DiscordExtractor):
     subcategory = "server"
-    pattern = rf"{BASE_PATTERN}/channels/(\d+)/?$"
+    pattern = BASE_PATTERN + r"/channels/(\d+)/?$"
     example = "https://discord.com/channels/1234567890"
 
     def items(self):
@@ -286,7 +286,7 @@ class DiscordDirectMessagesExtractor(DiscordExtractor):
     subcategory = "direct-messages"
     directory_fmt = ("{category}", "Direct Messages",
                      "{channel_id}_{recipients:J,}")
-    pattern = rf"{BASE_PATTERN}/channels/@me/(\d+)/?$"
+    pattern = BASE_PATTERN + r"/channels/@me/(\d+)/?$"
     example = "https://discord.com/channels/@me/1234567890"
 
     def items(self):
@@ -297,7 +297,7 @@ class DiscordDirectMessageExtractor(DiscordExtractor):
     subcategory = "direct-message"
     directory_fmt = ("{category}", "Direct Messages",
                      "{channel_id}_{recipients:J,}")
-    pattern = rf"{BASE_PATTERN}/channels/@me/(\d+)/(\d+)/?$"
+    pattern = BASE_PATTERN + r"/channels/@me/(\d+)/(\d+)/?$"
     example = "https://discord.com/channels/@me/1234567890/9876543210"
 
     def items(self):
diff --git a/gallery_dl/extractor/dynastyscans.py b/gallery_dl/extractor/dynastyscans.py
index 36423dba..e079d85a 100644
--- a/gallery_dl/extractor/dynastyscans.py
+++ b/gallery_dl/extractor/dynastyscans.py
@@ -41,7 +41,7 @@ class DynastyscansBase():
 
 class DynastyscansChapterExtractor(DynastyscansBase, ChapterExtractor):
     """Extractor for manga-chapters from dynasty-scans.com"""
-    pattern = rf"{BASE_PATTERN}(/chapters/[^/?#]+)"
+    pattern = BASE_PATTERN + r"(/chapters/[^/?#]+)"
     example = "https://dynasty-scans.com/chapters/NAME"
 
     def metadata(self, page):
@@ -81,7 +81,7 @@ class DynastyscansChapterExtractor(DynastyscansBase, ChapterExtractor):
 class DynastyscansMangaExtractor(DynastyscansBase, MangaExtractor):
     chapterclass = DynastyscansChapterExtractor
     reverse = False
-    pattern = rf"{BASE_PATTERN}(/series/[^/?#]+)"
+    pattern = BASE_PATTERN + r"(/series/[^/?#]+)"
     example = "https://dynasty-scans.com/series/NAME"
 
     def chapters(self, page):
@@ -97,7 +97,7 @@ class DynastyscansSearchExtractor(DynastyscansBase, Extractor):
     directory_fmt = ("{category}", "Images")
     filename_fmt = "{image_id}.{extension}"
     archive_fmt = "i_{image_id}"
-    pattern = rf"{BASE_PATTERN}/images/?(?:\?([^#]+))?$"
+    pattern = BASE_PATTERN + r"/images/?(?:\?([^#]+))?$"
     example = "https://dynasty-scans.com/images?QUERY"
 
     def __init__(self, match):
@@ -126,7 +126,7 @@ class DynastyscansSearchExtractor(DynastyscansBase, Extractor):
 class DynastyscansImageExtractor(DynastyscansSearchExtractor):
     """Extractor for individual images on dynasty-scans.com"""
     subcategory = "image"
-    pattern = rf"{BASE_PATTERN}/images/(\d+)"
+    pattern = BASE_PATTERN + r"/images/(\d+)"
     example = "https://dynasty-scans.com/images/12345"
 
     def images(self):
@@ -136,7 +136,7 @@ class DynastyscansImageExtractor(DynastyscansSearchExtractor):
 class DynastyscansAnthologyExtractor(DynastyscansSearchExtractor):
     """Extractor for dynasty-scans anthologies"""
     subcategory = "anthology"
-    pattern = rf"{BASE_PATTERN}/anthologies/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/anthologies/([^/?#]+)"
     example = "https://dynasty-scans.com/anthologies/TITLE"
 
     def items(self):
diff --git a/gallery_dl/extractor/e621.py b/gallery_dl/extractor/e621.py
index cc6708d5..08cab001 100644
--- a/gallery_dl/extractor/e621.py
+++ b/gallery_dl/extractor/e621.py
@@ -94,13 +94,13 @@ BASE_PATTERN = E621Extractor.update({
 
 class E621TagExtractor(E621Extractor, danbooru.DanbooruTagExtractor):
     """Extractor for e621 posts from tag searches"""
-    pattern = rf"{BASE_PATTERN}/posts?(?:\?[^#]*?tags=|/index/\d+/)([^&#]*)"
+    pattern = BASE_PATTERN + r"/posts?(?:\?[^#]*?tags=|/index/\d+/)([^&#]*)"
     example = "https://e621.net/posts?tags=TAG"
 
 
 class E621PoolExtractor(E621Extractor, danbooru.DanbooruPoolExtractor):
     """Extractor for e621 pools"""
-    pattern = rf"{BASE_PATTERN}/pool(?:s|/show)/(\d+)"
+    pattern = BASE_PATTERN + r"/pool(?:s|/show)/(\d+)"
     example = "https://e621.net/pools/12345"
 
     def posts(self):
@@ -125,7 +125,7 @@ class E621PoolExtractor(E621Extractor, danbooru.DanbooruPoolExtractor):
 
 class E621PostExtractor(E621Extractor, danbooru.DanbooruPostExtractor):
     """Extractor for single e621 posts"""
-    pattern = rf"{BASE_PATTERN}/post(?:s|/show)/(\d+)"
+    pattern = BASE_PATTERN + r"/post(?:s|/show)/(\d+)"
     example = "https://e621.net/posts/12345"
 
     def posts(self):
@@ -135,7 +135,7 @@ class E621PostExtractor(E621Extractor, danbooru.DanbooruPostExtractor):
 
 class E621PopularExtractor(E621Extractor, danbooru.DanbooruPopularExtractor):
     """Extractor for popular images from e621"""
-    pattern = rf"{BASE_PATTERN}/explore/posts/popular(?:\?([^#]*))?"
+    pattern = BASE_PATTERN + r"/explore/posts/popular(?:\?([^#]*))?"
     example = "https://e621.net/explore/posts/popular"
 
     def posts(self):
@@ -145,7 +145,7 @@ class E621PopularExtractor(E621Extractor, danbooru.DanbooruPopularExtractor):
 class E621ArtistExtractor(E621Extractor, danbooru.DanbooruArtistExtractor):
     """Extractor for e621 artists"""
     subcategory = "artist"
-    pattern = rf"{BASE_PATTERN}/artists/(\d+)"
+    pattern = BASE_PATTERN + r"/artists/(\d+)"
     example = "https://e621.net/artists/12345"
 
     items = E621Extractor.items_artists
@@ -155,7 +155,7 @@ class E621ArtistSearchExtractor(E621Extractor,
                                 danbooru.DanbooruArtistSearchExtractor):
     """Extractor for e621 artist searches"""
     subcategory = "artist-search"
-    pattern = rf"{BASE_PATTERN}/artists/?\?([^#]+)"
+    pattern = BASE_PATTERN + r"/artists/?\?([^#]+)"
     example = "https://e621.net/artists?QUERY"
 
     items = E621Extractor.items_artists
@@ -166,7 +166,7 @@ class E621FavoriteExtractor(E621Extractor):
     subcategory = "favorite"
     directory_fmt = ("{category}", "Favorites", "{user_id}")
     archive_fmt = "f_{user_id}_{id}"
-    pattern = rf"{BASE_PATTERN}/favorites(?:\?([^#]*))?"
+    pattern = BASE_PATTERN + r"/favorites(?:\?([^#]*))?"
     example = "https://e621.net/favorites"
 
     def metadata(self):
diff --git a/gallery_dl/extractor/erome.py b/gallery_dl/extractor/erome.py
index 2c9ab47b..d01d00a8 100644
--- a/gallery_dl/extractor/erome.py
+++ b/gallery_dl/extractor/erome.py
@@ -25,10 +25,10 @@ class EromeExtractor(Extractor):
     _cookies = True
 
     def items(self):
-        base = f"{self.root}/a/"
+        base = self.root + "/a/"
         data = {"_extractor": EromeAlbumExtractor}
         for album_id in self.albums():
-            yield Message.Queue, f"{base}{album_id}", data
+            yield Message.Queue, base + album_id, data
 
     def albums(self):
         return ()
@@ -64,7 +64,7 @@ class EromeExtractor(Extractor):
 class EromeAlbumExtractor(EromeExtractor):
     """Extractor for albums on erome.com"""
     subcategory = "album"
-    pattern = rf"{BASE_PATTERN}/a/(\w+)"
+    pattern = BASE_PATTERN + r"/a/(\w+)"
     example = "https://www.erome.com/a/ID"
 
     def items(self):
@@ -121,7 +121,7 @@ class EromeAlbumExtractor(EromeExtractor):
 
 class EromeUserExtractor(EromeExtractor):
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/(?!a/|search\?)([^/?#]+)(?:/?\?([^#]+))?"
+    pattern = BASE_PATTERN + r"/(?!a/|search\?)([^/?#]+)(?:/?\?([^#]+))?"
     example = "https://www.erome.com/USER"
 
     def albums(self):
@@ -137,11 +137,11 @@ class EromeUserExtractor(EromeExtractor):
 
 class EromeSearchExtractor(EromeExtractor):
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/search/?\?(q=[^#]+)"
+    pattern = BASE_PATTERN + r"/search/?\?(q=[^#]+)"
     example = "https://www.erome.com/search?q=QUERY"
 
     def albums(self):
-        url = f"{self.root}/search"
+        url = self.root + "/search"
         params = text.parse_query(self.groups[0])
         return self._pagination(url, params)
 
diff --git a/gallery_dl/extractor/everia.py b/gallery_dl/extractor/everia.py
index ce298002..8f1beceb 100644
--- a/gallery_dl/extractor/everia.py
+++ b/gallery_dl/extractor/everia.py
@@ -45,7 +45,7 @@ class EveriaPostExtractor(EveriaExtractor):
     subcategory = "post"
     directory_fmt = ("{category}", "{title}")
     archive_fmt = "{post_url}_{num}"
-    pattern = rf"{BASE_PATTERN}(/\d{{4}}/\d{{2}}/\d{{2}}/[^/?#]+)"
+    pattern = BASE_PATTERN + r"(/\d{4}/\d{2}/\d{2}/[^/?#]+)"
     example = "https://everia.club/0000/00/00/TITLE"
 
     def items(self):
@@ -72,26 +72,26 @@ class EveriaPostExtractor(EveriaExtractor):
 
 class EveriaTagExtractor(EveriaExtractor):
     subcategory = "tag"
-    pattern = rf"{BASE_PATTERN}(/tag/[^/?#]+)"
+    pattern = BASE_PATTERN + r"(/tag/[^/?#]+)"
     example = "https://everia.club/tag/TAG"
 
 
 class EveriaCategoryExtractor(EveriaExtractor):
     subcategory = "category"
-    pattern = rf"{BASE_PATTERN}(/category/[^/?#]+)"
+    pattern = BASE_PATTERN + r"(/category/[^/?#]+)"
     example = "https://everia.club/category/CATEGORY"
 
 
 class EveriaDateExtractor(EveriaExtractor):
     subcategory = "date"
-    pattern = (rf"{BASE_PATTERN}"
-               rf"(/\d{{4}}(?:/\d{{2}})?(?:/\d{{2}})?)(?:/page/\d+)?/?$")
+    pattern = (BASE_PATTERN +
+               r"(/\d{4}(?:/\d{2})?(?:/\d{2})?)(?:/page/\d+)?/?$")
     example = "https://everia.club/0000/00/00"
 
 
 class EveriaSearchExtractor(EveriaExtractor):
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/(?:page/\d+/)?\?s=([^&#]+)"
+    pattern = BASE_PATTERN + r"/(?:page/\d+/)?\?s=([^&#]+)"
     example = "https://everia.club/?s=SEARCH"
 
     def posts(self):
diff --git a/gallery_dl/extractor/exhentai.py b/gallery_dl/extractor/exhentai.py
index 881b3cd7..937e863f 100644
--- a/gallery_dl/extractor/exhentai.py
+++ b/gallery_dl/extractor/exhentai.py
@@ -115,9 +115,9 @@ class ExhentaiExtractor(Extractor):
 class ExhentaiGalleryExtractor(ExhentaiExtractor):
     """Extractor for image galleries from exhentai.org"""
     subcategory = "gallery"
-    pattern = (rf"{BASE_PATTERN}/(?:"
-               rf"g/(\d+)/([\da-f]{{10}})|"
-               rf"s/([\da-f]{{10}})/(\d+)-(\d+))")
+    pattern = (BASE_PATTERN +
+               r"(?:/g/(\d+)/([\da-f]{10})"
+               r"|/s/([\da-f]{10})/(\d+)-(\d+))")
     example = "https://e-hentai.org/g/12345/67890abcde/"
 
     def __init__(self, match):
@@ -562,7 +562,7 @@ class ExhentaiGalleryExtractor(ExhentaiExtractor):
 class ExhentaiSearchExtractor(ExhentaiExtractor):
     """Extractor for exhentai search results"""
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/(?:\?([^#]*)|tag/([^/?#]+))"
+    pattern = BASE_PATTERN + r"/(?:\?([^#]*)|tag/([^/?#]+))"
     example = "https://e-hentai.org/?f_search=QUERY"
 
     def __init__(self, match):
@@ -619,7 +619,7 @@ class ExhentaiSearchExtractor(ExhentaiExtractor):
 class ExhentaiFavoriteExtractor(ExhentaiSearchExtractor):
     """Extractor for favorited exhentai galleries"""
     subcategory = "favorite"
-    pattern = rf"{BASE_PATTERN}/favorites\.php(?:\?([^#]*)())?"
+    pattern = BASE_PATTERN + r"/favorites\.php(?:\?([^#]*)())?"
     example = "https://e-hentai.org/favorites.php"
 
     def _init(self):
diff --git a/gallery_dl/extractor/facebook.py b/gallery_dl/extractor/facebook.py
index bedf45c1..7f03f846 100644
--- a/gallery_dl/extractor/facebook.py
+++ b/gallery_dl/extractor/facebook.py
@@ -11,9 +11,9 @@ from .. import text, util, exception
 from ..cache import memcache
 
 BASE_PATTERN = r"(?:https?://)?(?:[\w-]+\.)?facebook\.com"
-USER_PATTERN = (rf"{BASE_PATTERN}/"
-                rf"(?!media/|photo/|photo.php|watch/|permalink.php)"
-                rf"(?:profile\.php\?id=|people/[^/?#]+/)?([^/?&#]+)")
+USER_PATTERN = (BASE_PATTERN +
+                r"/(?!media/|photo/|photo.php|watch/|permalink.php)"
+                r"(?:profile\.php\?id=|people/[^/?#]+/)?([^/?&#]+)")
 
 
 class FacebookExtractor(Extractor):
@@ -237,16 +237,14 @@ class FacebookExtractor(Extractor):
 
         if res.url.startswith(self.root + "/login"):
             raise exception.AuthRequired(
-                message=(f"You must be logged in to continue viewing images."
-                         f"{LEFT_OFF_TXT}")
-            )
+                message=("You must be logged in to continue viewing images." +
+                         LEFT_OFF_TXT))
 
         if b'{"__dr":"CometErrorRoot.react"}' in res.content:
             raise exception.AbortExtraction(
-                f"You've been temporarily blocked from viewing images.\n"
-                f"Please try using a different account, "
-                f"using a VPN or waiting before you retry.{LEFT_OFF_TXT}"
-            )
+                "You've been temporarily blocked from viewing images.\n"
+                "Please try using a different account, "
+                "using a VPN or waiting before you retry." + LEFT_OFF_TXT)
 
         return res
 
@@ -395,9 +393,9 @@ class FacebookExtractor(Extractor):
 class FacebookPhotoExtractor(FacebookExtractor):
     """Base class for Facebook Photo extractors"""
     subcategory = "photo"
-    pattern = (rf"{BASE_PATTERN}/"
-               rf"(?:[^/?#]+/photos/[^/?#]+/|photo(?:.php)?/?\?"
-               rf"(?:[^&#]+&)*fbid=)([^/?&#]+)[^/?#]*(?<!&setextract)$")
+    pattern = (BASE_PATTERN +
+               r"/(?:[^/?#]+/photos/[^/?#]+/|photo(?:.php)?/?\?"
+               r"(?:[^&#]+&)*fbid=)([^/?&#]+)[^/?#]*(?<!&setextract)$")
     example = "https://www.facebook.com/photo/?fbid=PHOTO_ID"
 
     def items(self):
@@ -433,11 +431,12 @@ class FacebookSetExtractor(FacebookExtractor):
     """Base class for Facebook Set extractors"""
     subcategory = "set"
     pattern = (
-        rf"{BASE_PATTERN}/"
-        rf"(?:(?:media/set|photo)/?\?(?:[^&#]+&)*set=([^&#]+)"
-        rf"[^/?#]*(?<!&setextract)$"
-        rf"|([^/?#]+/posts/[^/?#]+)"
-        rf"|photo/\?(?:[^&#]+&)*fbid=([^/?&#]+)&set=([^/?&#]+)&setextract)")
+        BASE_PATTERN +
+        r"/(?:(?:media/set|photo)/?\?(?:[^&#]+&)*set=([^&#]+)"
+        r"[^/?#]*(?<!&setextract)$"
+        r"|([^/?#]+/posts/[^/?#]+)"
+        r"|photo/\?(?:[^&#]+&)*fbid=([^/?&#]+)&set=([^/?&#]+)&setextract)"
+    )
     example = "https://www.facebook.com/media/set/?set=SET_ID"
 
     def items(self):
@@ -460,7 +459,7 @@ class FacebookVideoExtractor(FacebookExtractor):
     """Base class for Facebook Video extractors"""
     subcategory = "video"
     directory_fmt = ("{category}", "{username}", "{subcategory}")
-    pattern = rf"{BASE_PATTERN}/(?:[^/?#]+/videos/|watch/?\?v=)([^/?&#]+)"
+    pattern = BASE_PATTERN + r"/(?:[^/?#]+/videos/|watch/?\?v=)([^/?&#]+)"
     example = "https://www.facebook.com/watch/?v=VIDEO_ID"
 
     def items(self):
@@ -487,7 +486,7 @@ class FacebookInfoExtractor(FacebookExtractor):
     """Extractor for Facebook Profile data"""
     subcategory = "info"
     directory_fmt = ("{category}", "{username}")
-    pattern = rf"{USER_PATTERN}/info"
+    pattern = USER_PATTERN + r"/info"
     example = "https://www.facebook.com/USERNAME/info"
 
     def items(self):
@@ -498,7 +497,7 @@ class FacebookInfoExtractor(FacebookExtractor):
 class FacebookAlbumsExtractor(FacebookExtractor):
     """Extractor for Facebook Profile albums"""
     subcategory = "albums"
-    pattern = rf"{USER_PATTERN}/photos_albums(?:/([^/?#]+))?"
+    pattern = USER_PATTERN + r"/photos_albums(?:/([^/?#]+))?"
     example = "https://www.facebook.com/USERNAME/photos_albums"
 
     def items(self):
@@ -531,7 +530,7 @@ class FacebookAlbumsExtractor(FacebookExtractor):
 class FacebookPhotosExtractor(FacebookExtractor):
     """Extractor for Facebook Profile Photos"""
     subcategory = "photos"
-    pattern = rf"{USER_PATTERN}/photos(?:_by)?"
+    pattern = USER_PATTERN + r"/photos(?:_by)?"
     example = "https://www.facebook.com/USERNAME/photos"
 
     def items(self):
@@ -548,7 +547,7 @@ class FacebookPhotosExtractor(FacebookExtractor):
 class FacebookAvatarExtractor(FacebookExtractor):
     """Extractor for Facebook Profile Avatars"""
     subcategory = "avatar"
-    pattern = rf"{USER_PATTERN}/avatar"
+    pattern = USER_PATTERN + r"/avatar"
     example = "https://www.facebook.com/USERNAME/avatar"
 
     def items(self):
@@ -570,7 +569,7 @@ class FacebookAvatarExtractor(FacebookExtractor):
 
 class FacebookUserExtractor(Dispatch, FacebookExtractor):
     """Extractor for Facebook Profiles"""
-    pattern = rf"{USER_PATTERN}/?(?:$|\?|#)"
+    pattern = USER_PATTERN + r"/?(?:$|\?|#)"
     example = "https://www.facebook.com/USERNAME"
 
     def items(self):
diff --git a/gallery_dl/extractor/fanbox.py b/gallery_dl/extractor/fanbox.py
index 036b3884..5af60449 100644
--- a/gallery_dl/extractor/fanbox.py
+++ b/gallery_dl/extractor/fanbox.py
@@ -340,7 +340,7 @@ class FanboxExtractor(Extractor):
             url = (f"https://docs.google.com/forms/d/e/"
                    f"{content_id}/viewform?usp=sf_link")
         else:
-            self.log.warning(f"service not recognized: {provider}")
+            self.log.warning("service not recognized: %s", provider)
 
         if url:
             final_post["embed"] = embed
@@ -355,7 +355,7 @@ class FanboxExtractor(Extractor):
 class FanboxCreatorExtractor(FanboxExtractor):
     """Extractor for a Fanbox creator's works"""
     subcategory = "creator"
-    pattern = rf"{USER_PATTERN}(?:/posts)?/?$"
+    pattern = USER_PATTERN + r"(?:/posts)?/?$"
     example = "https://USER.fanbox.cc/"
 
     def posts(self):
@@ -384,7 +384,7 @@ class FanboxCreatorExtractor(FanboxExtractor):
 class FanboxPostExtractor(FanboxExtractor):
     """Extractor for media from a single Fanbox post"""
     subcategory = "post"
-    pattern = rf"{USER_PATTERN}/posts/(\d+)"
+    pattern = USER_PATTERN + r"/posts/(\d+)"
     example = "https://USER.fanbox.cc/posts/12345"
 
     def posts(self):
@@ -394,7 +394,7 @@ class FanboxPostExtractor(FanboxExtractor):
 class FanboxHomeExtractor(FanboxExtractor):
     """Extractor for your Fanbox home feed"""
     subcategory = "home"
-    pattern = rf"{BASE_PATTERN}/?$"
+    pattern = BASE_PATTERN + r"/?$"
     example = "https://fanbox.cc/"
 
     def posts(self):
@@ -405,7 +405,7 @@ class FanboxHomeExtractor(FanboxExtractor):
 class FanboxSupportingExtractor(FanboxExtractor):
     """Extractor for your supported Fanbox users feed"""
     subcategory = "supporting"
-    pattern = rf"{BASE_PATTERN}/home/supporting"
+    pattern = BASE_PATTERN + r"/home/supporting"
     example = "https://fanbox.cc/home/supporting"
 
     def posts(self):
diff --git a/gallery_dl/extractor/fansly.py b/gallery_dl/extractor/fansly.py
index ba60b158..d57c8ca4 100644
--- a/gallery_dl/extractor/fansly.py
+++ b/gallery_dl/extractor/fansly.py
@@ -135,7 +135,7 @@ class FanslyExtractor(Extractor):
 
             files.append({
                 "file": file,
-                "url": f"ytdl:{location['location']}",
+                "url": "ytdl:" + location["location"],
                 "_fallback": fallback,
                 "_ytdl_manifest":
                     "dash" if mime == "application/dash+xml" else "hls",
@@ -155,7 +155,7 @@ class FanslyExtractor(Extractor):
 
 class FanslyPostExtractor(FanslyExtractor):
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/post/(\d+)"
+    pattern = BASE_PATTERN + r"/post/(\d+)"
     example = "https://fansly.com/post/1234567890"
 
     def posts(self):
@@ -164,7 +164,7 @@ class FanslyPostExtractor(FanslyExtractor):
 
 class FanslyHomeExtractor(FanslyExtractor):
     subcategory = "home"
-    pattern = rf"{BASE_PATTERN}/home(?:/(?:subscribed()|list/(\d+)))?"
+    pattern = BASE_PATTERN + r"/home(?:/(?:subscribed()|list/(\d+)))?"
     example = "https://fansly.com/home"
 
     def posts(self):
@@ -180,11 +180,11 @@ class FanslyHomeExtractor(FanslyExtractor):
 
 class FanslyListExtractor(FanslyExtractor):
     subcategory = "list"
-    pattern = rf"{BASE_PATTERN}/lists/(\d+)"
+    pattern = BASE_PATTERN + r"/lists/(\d+)"
     example = "https://fansly.com/lists/1234567890"
 
     def items(self):
-        base = f"{self.root}/"
+        base = self.root + "/"
         for account in self.api.lists_itemsnew(self.groups[0]):
             account["_extractor"] = FanslyCreatorPostsExtractor
             url = f"{base}{account['username']}/posts"
@@ -193,11 +193,11 @@ class FanslyListExtractor(FanslyExtractor):
 
 class FanslyListsExtractor(FanslyExtractor):
     subcategory = "lists"
-    pattern = rf"{BASE_PATTERN}/lists"
+    pattern = BASE_PATTERN + r"/lists"
     example = "https://fansly.com/lists"
 
     def items(self):
-        base = f"{self.root}/lists/"
+        base = self.root + "/lists/"
         for list in self.api.lists_account():
             list["_extractor"] = FanslyListExtractor
             url = f"{base}{list['id']}#{list['label']}"
@@ -206,7 +206,7 @@ class FanslyListsExtractor(FanslyExtractor):
 
 class FanslyCreatorPostsExtractor(FanslyExtractor):
     subcategory = "creator-posts"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/posts(?:/wall/(\d+))?"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/posts(?:/wall/(\d+))?"
     example = "https://fansly.com/CREATOR/posts"
 
     def posts_wall(self, account, wall):
@@ -215,7 +215,7 @@ class FanslyCreatorPostsExtractor(FanslyExtractor):
 
 class FanslyCreatorMediaExtractor(FanslyExtractor):
     subcategory = "creator-media"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/media(?:/wall/(\d+))?"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/media(?:/wall/(\d+))?"
     example = "https://fansly.com/CREATOR/media"
 
     def posts_wall(self, account, wall):
@@ -308,7 +308,7 @@ class FanslyAPI():
         return self._pagination(endpoint, params)
 
     def timeline_new(self, account_id, wall_id):
-        endpoint = f"/v1/timelinenew/{account_id}"
+        endpoint = "/v1/timelinenew/" + str(account_id)
         params = {
             "before"       : "0",
             "after"        : "0",
diff --git a/gallery_dl/extractor/fapello.py b/gallery_dl/extractor/fapello.py
index afef9427..2bd7a1fc 100644
--- a/gallery_dl/extractor/fapello.py
+++ b/gallery_dl/extractor/fapello.py
@@ -20,7 +20,7 @@ class FapelloPostExtractor(Extractor):
     directory_fmt = ("{category}", "{model}")
     filename_fmt = "{model}_{id}.{extension}"
     archive_fmt = "{type}_{model}_{id}"
-    pattern = rf"{BASE_PATTERN}/(?!search/|popular_videos/)([^/?#]+)/(\d+)"
+    pattern = BASE_PATTERN + r"/(?!search/|popular_videos/)([^/?#]+)/(\d+)"
     example = "https://fapello.com/MODEL/12345/"
 
     def __init__(self, match):
@@ -52,9 +52,9 @@ class FapelloModelExtractor(Extractor):
     """Extractor for all posts from a fapello model"""
     category = "fapello"
     subcategory = "model"
-    pattern = (rf"{BASE_PATTERN}/(?!top-(?:likes|followers)|popular_videos"
-               rf"|videos|trending|search/?$)"
-               rf"([^/?#]+)/?$")
+    pattern = (BASE_PATTERN + r"/(?!top-(?:likes|followers)|popular_videos"
+               r"|videos|trending|search/?$)"
+               r"([^/?#]+)/?$")
     example = "https://fapello.com/model/"
 
     def __init__(self, match):
@@ -85,9 +85,9 @@ class FapelloPathExtractor(Extractor):
     """Extractor for models and posts from fapello.com paths"""
     category = "fapello"
     subcategory = "path"
-    pattern = (rf"{BASE_PATTERN}/(?!search/?$)"
-               rf"(top-(?:likes|followers)|videos|trending"
-               rf"|popular_videos/[^/?#]+)/?$")
+    pattern = (BASE_PATTERN +
+               r"/(?!search/?$)(top-(?:likes|followers)|videos|trending"
+               r"|popular_videos/[^/?#]+)/?$")
     example = "https://fapello.com/trending/"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/fikfap.py b/gallery_dl/extractor/fikfap.py
index 75071c56..5a0f4347 100644
--- a/gallery_dl/extractor/fikfap.py
+++ b/gallery_dl/extractor/fikfap.py
@@ -67,7 +67,7 @@ class FikfapExtractor(Extractor):
 
 class FikfapPostExtractor(FikfapExtractor):
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/user/(\w+)/post/(\d+)"
+    pattern = BASE_PATTERN + r"/user/(\w+)/post/(\d+)"
     example = "https://fikfap.com/user/USER/post/12345"
 
     def posts(self):
@@ -86,7 +86,7 @@ class FikfapPostExtractor(FikfapExtractor):
 
 class FikfapUserExtractor(FikfapExtractor):
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/user/(\w+)"
+    pattern = BASE_PATTERN + r"/user/(\w+)"
     example = "https://fikfap.com/user/USER"
 
     def posts(self):
diff --git a/gallery_dl/extractor/fitnakedgirls.py b/gallery_dl/extractor/fitnakedgirls.py
index d252ec4f..a1ebf48a 100644
--- a/gallery_dl/extractor/fitnakedgirls.py
+++ b/gallery_dl/extractor/fitnakedgirls.py
@@ -50,7 +50,7 @@ class FitnakedgirlsGalleryExtractor(GalleryExtractor, FitnakedgirlsExtractor):
     directory_fmt = ("{category}", "{title}")
     filename_fmt = "{filename}.{extension}"
     archive_fmt = "{gallery_id}_{filename}"
-    pattern = rf"{BASE_PATTERN}/photos/gallery/([\w-]+)/?$"
+    pattern = BASE_PATTERN + r"/photos/gallery/([\w-]+)/?$"
     example = "https://fitnakedgirls.com/photos/gallery/MODEL-nude/"
 
     def __init__(self, match):
@@ -110,7 +110,7 @@ class FitnakedgirlsGalleryExtractor(GalleryExtractor, FitnakedgirlsExtractor):
 class FitnakedgirlsCategoryExtractor(FitnakedgirlsExtractor):
     """Extractor for fitnakedgirls category pages"""
     subcategory = "category"
-    pattern = rf"{BASE_PATTERN}/photos/gallery/category/([\w-]+)"
+    pattern = BASE_PATTERN + r"/photos/gallery/category/([\w-]+)"
     example = "https://fitnakedgirls.com/photos/gallery/category/CATEGORY/"
 
     def galleries(self):
@@ -121,7 +121,7 @@ class FitnakedgirlsCategoryExtractor(FitnakedgirlsExtractor):
 class FitnakedgirlsTagExtractor(FitnakedgirlsExtractor):
     """Extractor for fitnakedgirls tag pages"""
     subcategory = "tag"
-    pattern = rf"{BASE_PATTERN}/photos/gallery/tag/([\w-]+)"
+    pattern = BASE_PATTERN + r"/photos/gallery/tag/([\w-]+)"
     example = "https://fitnakedgirls.com/photos/gallery/tag/TAG/"
 
     def galleries(self):
@@ -135,7 +135,7 @@ class FitnakedgirlsVideoExtractor(FitnakedgirlsExtractor):
     directory_fmt = ("{category}", "{title}")
     filename_fmt = "{filename}.{extension}"
     archive_fmt = "{video_id}_{filename}"
-    pattern = rf"{BASE_PATTERN}/videos/(\d+)/(\d+)/([\w-]+)"
+    pattern = BASE_PATTERN + r"/videos/(\d+)/(\d+)/([\w-]+)"
     example = "https://fitnakedgirls.com/videos/2025/08/VIDEO-TITLE/"
 
     def items(self):
@@ -168,7 +168,7 @@ class FitnakedgirlsBlogExtractor(FitnakedgirlsExtractor):
     directory_fmt = ("{category}", "{title}")
     filename_fmt = "{filename}.{extension}"
     archive_fmt = "{post_id}_{filename}"
-    pattern = rf"{BASE_PATTERN}/fitblog/([\w-]+)"
+    pattern = BASE_PATTERN + r"/fitblog/([\w-]+)"
     example = "https://fitnakedgirls.com/fitblog/MODEL-NAME/"
 
     def items(self):
diff --git a/gallery_dl/extractor/flickr.py b/gallery_dl/extractor/flickr.py
index 1446eb87..5071de7e 100644
--- a/gallery_dl/extractor/flickr.py
+++ b/gallery_dl/extractor/flickr.py
@@ -124,7 +124,7 @@ class FlickrAlbumExtractor(FlickrExtractor):
     directory_fmt = ("{category}", "{user[username]}",
                      "Albums", "{album[id]} {album[title]}")
     archive_fmt = "a_{album[id]}_{id}"
-    pattern = rf"{BASE_PATTERN}/photos/([^/?#]+)/(?:album|set)s(?:/(\d+))?"
+    pattern = BASE_PATTERN + r"/photos/([^/?#]+)/(?:album|set)s(?:/(\d+))?"
     example = "https://www.flickr.com/photos/USER/albums/12345"
 
     def items(self):
@@ -166,7 +166,7 @@ class FlickrGalleryExtractor(FlickrExtractor):
     directory_fmt = ("{category}", "{user[username]}",
                      "Galleries", "{gallery[gallery_id]} {gallery[title]}")
     archive_fmt = "g_{gallery[id]}_{id}"
-    pattern = rf"{BASE_PATTERN}/photos/([^/?#]+)/galleries/(\d+)"
+    pattern = BASE_PATTERN + r"/photos/([^/?#]+)/galleries/(\d+)"
     example = "https://www.flickr.com/photos/USER/galleries/12345/"
 
     def metadata(self):
@@ -184,7 +184,7 @@ class FlickrGroupExtractor(FlickrExtractor):
     subcategory = "group"
     directory_fmt = ("{category}", "Groups", "{group[groupname]}")
     archive_fmt = "G_{group[nsid]}_{id}"
-    pattern = rf"{BASE_PATTERN}/groups/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/groups/([^/?#]+)"
     example = "https://www.flickr.com/groups/NAME/"
 
     def metadata(self):
@@ -199,7 +199,7 @@ class FlickrUserExtractor(FlickrExtractor):
     """Extractor for the photostream of a flickr user"""
     subcategory = "user"
     archive_fmt = "u_{user[nsid]}_{id}"
-    pattern = rf"{BASE_PATTERN}/photos/([^/?#]+)/?$"
+    pattern = BASE_PATTERN + r"/photos/([^/?#]+)/?$"
     example = "https://www.flickr.com/photos/USER/"
 
     def photos(self):
@@ -211,7 +211,7 @@ class FlickrFavoriteExtractor(FlickrExtractor):
     subcategory = "favorite"
     directory_fmt = ("{category}", "{user[username]}", "Favorites")
     archive_fmt = "f_{user[nsid]}_{id}"
-    pattern = rf"{BASE_PATTERN}/photos/([^/?#]+)/favorites"
+    pattern = BASE_PATTERN + r"/photos/([^/?#]+)/favorites"
     example = "https://www.flickr.com/photos/USER/favorites"
 
     def photos(self):
@@ -223,7 +223,7 @@ class FlickrSearchExtractor(FlickrExtractor):
     subcategory = "search"
     directory_fmt = ("{category}", "Search", "{search[text]}")
     archive_fmt = "s_{search}_{id}"
-    pattern = rf"{BASE_PATTERN}/search/?\?([^#]+)"
+    pattern = BASE_PATTERN + r"/search/?\?([^#]+)"
     example = "https://flickr.com/search/?text=QUERY"
 
     def metadata(self):
@@ -456,7 +456,7 @@ class FlickrAPI(oauth.OAuth1API):
         except ValueError:
             data = {"code": -1, "message": response.content}
         if "code" in data:
-            msg = data.get("message")
+            msg = data.get("message", "")
             self.log.debug("Server response: %s", data)
             if data["code"] == 1:
                 raise exception.NotFoundError(self.extractor.subcategory)
@@ -466,7 +466,7 @@ class FlickrAPI(oauth.OAuth1API):
                 raise exception.AuthenticationError(msg)
             elif data["code"] == 99:
                 raise exception.AuthorizationError(msg)
-            raise exception.AbortExtraction(f"API request failed: {msg}")
+            raise exception.AbortExtraction("API request failed: " + msg)
         return data
 
     def _pagination(self, method, params, key="photos"):
diff --git a/gallery_dl/extractor/foolfuuka.py b/gallery_dl/extractor/foolfuuka.py
index 3c694896..88053b4c 100644
--- a/gallery_dl/extractor/foolfuuka.py
+++ b/gallery_dl/extractor/foolfuuka.py
@@ -147,7 +147,7 @@ class FoolfuukaThreadExtractor(FoolfuukaExtractor):
     subcategory = "thread"
     directory_fmt = ("{category}", "{board[shortname]}",
                      "{thread_num} {title|comment[:50]}")
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/thread/(\d+)"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/thread/(\d+)"
     example = "https://archived.moe/a/thread/12345/"
 
     def __init__(self, match):
@@ -174,7 +174,7 @@ class FoolfuukaThreadExtractor(FoolfuukaExtractor):
 class FoolfuukaBoardExtractor(FoolfuukaExtractor):
     """Base extractor for FoolFuuka based boards/archives"""
     subcategory = "board"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)(?:/(?:page/)?(\d*))?$"
+    pattern = BASE_PATTERN + r"/([^/?#]+)(?:/(?:page/)?(\d*))?$"
     example = "https://archived.moe/a/"
 
     def __init__(self, match):
@@ -210,7 +210,7 @@ class FoolfuukaSearchExtractor(FoolfuukaExtractor):
     """Base extractor for search results on FoolFuuka based boards/archives"""
     subcategory = "search"
     directory_fmt = ("{category}", "search", "{search}")
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/search((?:/[^/?#]+/[^/?#]+)+)"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/search((?:/[^/?#]+/[^/?#]+)+)"
     example = "https://archived.moe/_/search/text/QUERY/"
     request_interval = (0.5, 1.5)
 
@@ -265,7 +265,7 @@ class FoolfuukaGalleryExtractor(FoolfuukaExtractor):
     """Base extractor for FoolFuuka galleries"""
     subcategory = "gallery"
     directory_fmt = ("{category}", "{board}", "gallery")
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/gallery(?:/(\d+))?"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/gallery(?:/(\d+))?"
     example = "https://archived.moe/a/gallery"
 
     def metadata(self):
@@ -278,7 +278,7 @@ class FoolfuukaGalleryExtractor(FoolfuukaExtractor):
         base = f"{self.root}/_/api/chan/gallery/?board={self.board}&page="
 
         for pnum in pages:
-            posts = self.request_json(f"{base}{pnum}")
+            posts = self.request_json(base + str(pnum))
             if not posts:
                 return
             yield from posts
diff --git a/gallery_dl/extractor/foolslide.py b/gallery_dl/extractor/foolslide.py
index d932174b..1f1f8398 100644
--- a/gallery_dl/extractor/foolslide.py
+++ b/gallery_dl/extractor/foolslide.py
@@ -47,7 +47,7 @@ class FoolslideChapterExtractor(FoolslideExtractor):
     filename_fmt = (
         "{manga}_c{chapter:>03}{chapter_minor:?//}_{page:>03}.{extension}")
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}(/read/[^/?#]+/[a-z-]+/\d+/\d+(?:/\d+)?)"
+    pattern = BASE_PATTERN + r"(/read/[^/?#]+/[a-z-]+/\d+/\d+(?:/\d+)?)"
     example = "https://read.powermanga.org/read/MANGA/en/0/123/"
 
     def items(self):
@@ -91,7 +91,7 @@ class FoolslideMangaExtractor(FoolslideExtractor):
     """Base class for manga extractors for FoOlSlide based sites"""
     subcategory = "manga"
     categorytransfer = True
-    pattern = rf"{BASE_PATTERN}(/series/[^/?#]+)"
+    pattern = BASE_PATTERN + r"(/series/[^/?#]+)"
     example = "https://read.powermanga.org/series/MANGA/"
 
     def items(self):
diff --git a/gallery_dl/extractor/furaffinity.py b/gallery_dl/extractor/furaffinity.py
index ad57a6b4..0a046c93 100644
--- a/gallery_dl/extractor/furaffinity.py
+++ b/gallery_dl/extractor/furaffinity.py
@@ -231,7 +231,7 @@ class FuraffinityExtractor(Extractor):
 class FuraffinityGalleryExtractor(FuraffinityExtractor):
     """Extractor for a furaffinity user's gallery"""
     subcategory = "gallery"
-    pattern = rf"{BASE_PATTERN}/gallery/([^/?#]+)(?:$|/(?!folder/))"
+    pattern = BASE_PATTERN + r"/gallery/([^/?#]+)(?:$|/(?!folder/))"
     example = "https://www.furaffinity.net/gallery/USER/"
 
     def posts(self):
@@ -243,7 +243,7 @@ class FuraffinityFolderExtractor(FuraffinityExtractor):
     subcategory = "folder"
     directory_fmt = ("{category}", "{user!l}",
                      "Folders", "{folder_id}{folder_name:? //}")
-    pattern = rf"{BASE_PATTERN}/gallery/([^/?#]+)/folder/(\d+)(?:/([^/?#]+))?"
+    pattern = BASE_PATTERN + r"/gallery/([^/?#]+)/folder/(\d+)(?:/([^/?#]+))?"
     example = "https://www.furaffinity.net/gallery/USER/folder/12345/FOLDER"
 
     def metadata(self):
@@ -260,7 +260,7 @@ class FuraffinityScrapsExtractor(FuraffinityExtractor):
     """Extractor for a furaffinity user's scraps"""
     subcategory = "scraps"
     directory_fmt = ("{category}", "{user!l}", "Scraps")
-    pattern = rf"{BASE_PATTERN}/scraps/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/scraps/([^/?#]+)"
     example = "https://www.furaffinity.net/scraps/USER/"
 
     def posts(self):
@@ -271,7 +271,7 @@ class FuraffinityFavoriteExtractor(FuraffinityExtractor):
     """Extractor for a furaffinity user's favorites"""
     subcategory = "favorite"
     directory_fmt = ("{category}", "{user!l}", "Favorites")
-    pattern = rf"{BASE_PATTERN}/favorites/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/favorites/([^/?#]+)"
     example = "https://www.furaffinity.net/favorites/USER/"
 
     def posts(self):
@@ -287,7 +287,7 @@ class FuraffinitySearchExtractor(FuraffinityExtractor):
     """Extractor for furaffinity search results"""
     subcategory = "search"
     directory_fmt = ("{category}", "Search", "{search}")
-    pattern = rf"{BASE_PATTERN}/search(?:/([^/?#]+))?/?[?&]([^#]+)"
+    pattern = BASE_PATTERN + r"/search(?:/([^/?#]+))?/?[?&]([^#]+)"
     example = "https://www.furaffinity.net/search/?q=QUERY"
 
     def __init__(self, match):
@@ -306,7 +306,7 @@ class FuraffinitySearchExtractor(FuraffinityExtractor):
 class FuraffinityPostExtractor(FuraffinityExtractor):
     """Extractor for individual posts on furaffinity"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/(?:view|full)/(\d+)"
+    pattern = BASE_PATTERN + r"/(?:view|full)/(\d+)"
     example = "https://www.furaffinity.net/view/12345/"
 
     def posts(self):
@@ -317,12 +317,12 @@ class FuraffinityPostExtractor(FuraffinityExtractor):
 
 class FuraffinityUserExtractor(Dispatch, FuraffinityExtractor):
     """Extractor for furaffinity user profiles"""
-    pattern = rf"{BASE_PATTERN}/user/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/user/([^/?#]+)"
     example = "https://www.furaffinity.net/user/USER/"
 
     def items(self):
         base = self.root
-        user = f"{self.user}/"
+        user = self.user + "/"
         return self._dispatch_extractors((
             (FuraffinityGalleryExtractor , f"{base}/gallery/{user}"),
             (FuraffinityScrapsExtractor  , f"{base}/scraps/{user}"),
@@ -333,7 +333,7 @@ class FuraffinityUserExtractor(Dispatch, FuraffinityExtractor):
 class FuraffinityFollowingExtractor(FuraffinityExtractor):
     """Extractor for a furaffinity user's watched users"""
     subcategory = "following"
-    pattern = rf"{BASE_PATTERN}/watchlist/by/([^/?#]+)"
+    pattern = BASE_PATTERN + "/watchlist/by/([^/?#]+)"
     example = "https://www.furaffinity.net/watchlist/by/USER/"
 
     def items(self):
@@ -355,7 +355,7 @@ class FuraffinityFollowingExtractor(FuraffinityExtractor):
 class FuraffinitySubmissionsExtractor(FuraffinityExtractor):
     """Extractor for new furaffinity submissions"""
     subcategory = "submissions"
-    pattern = rf"{BASE_PATTERN}(/msg/submissions(?:/[^/?#]+)?)"
+    pattern = BASE_PATTERN + r"(/msg/submissions(?:/[^/?#]+)?)"
     example = "https://www.furaffinity.net/msg/submissions"
 
     def posts(self):
diff --git a/gallery_dl/extractor/furry34.py b/gallery_dl/extractor/furry34.py
index 95b98dbb..3673edb0 100644
--- a/gallery_dl/extractor/furry34.py
+++ b/gallery_dl/extractor/furry34.py
@@ -97,7 +97,7 @@ class Furry34Extractor(BooruExtractor):
 class Furry34PostExtractor(Furry34Extractor):
     subcategory = "post"
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}/post/(\d+)"
+    pattern = BASE_PATTERN + r"/post/(\d+)"
     example = "https://furry34.com/post/12345"
 
     def posts(self):
@@ -108,7 +108,7 @@ class Furry34PlaylistExtractor(Furry34Extractor):
     subcategory = "playlist"
     directory_fmt = ("{category}", "{playlist_id}")
     archive_fmt = "p_{playlist_id}_{id}"
-    pattern = rf"{BASE_PATTERN}/playlists/view/(\d+)"
+    pattern = BASE_PATTERN + r"/playlists/view/(\d+)"
     example = "https://furry34.com/playlists/view/12345"
 
     def metadata(self):
@@ -123,7 +123,7 @@ class Furry34TagExtractor(Furry34Extractor):
     subcategory = "tag"
     directory_fmt = ("{category}", "{search_tags}")
     archive_fmt = "t_{search_tags}_{id}"
-    pattern = rf"{BASE_PATTERN}/(?:([^/?#]+))?(?:/?\?([^#]+))?(?:$|#)"
+    pattern = BASE_PATTERN + r"/(?:([^/?#]+))?(?:/?\?([^#]+))?(?:$|#)"
     example = "https://furry34.com/TAG"
 
     def _init(self):
diff --git a/gallery_dl/extractor/gelbooru.py b/gallery_dl/extractor/gelbooru.py
index 0571fcd2..ffba38ab 100644
--- a/gallery_dl/extractor/gelbooru.py
+++ b/gallery_dl/extractor/gelbooru.py
@@ -148,7 +148,7 @@ class GelbooruBase():
 class GelbooruTagExtractor(GelbooruBase,
                            gelbooru_v02.GelbooruV02TagExtractor):
     """Extractor for images from gelbooru.com based on search-tags"""
-    pattern = rf"{BASE_PATTERN}page=post&s=list&tags=([^&#]*)"
+    pattern = BASE_PATTERN + r"page=post&s=list&tags=([^&#]*)"
     example = "https://gelbooru.com/index.php?page=post&s=list&tags=TAG"
 
 
@@ -156,7 +156,7 @@ class GelbooruPoolExtractor(GelbooruBase,
                             gelbooru_v02.GelbooruV02PoolExtractor):
     """Extractor for gelbooru pools"""
     per_page = 45
-    pattern = rf"{BASE_PATTERN}page=pool&s=show&id=(\d+)"
+    pattern = BASE_PATTERN + r"page=pool&s=show&id=(\d+)"
     example = "https://gelbooru.com/index.php?page=pool&s=show&id=12345"
 
     skip = GelbooruBase._skip_offset
@@ -187,7 +187,7 @@ class GelbooruFavoriteExtractor(GelbooruBase,
                                 gelbooru_v02.GelbooruV02FavoriteExtractor):
     """Extractor for gelbooru favorites"""
     per_page = 100
-    pattern = rf"{BASE_PATTERN}page=favorites&s=view&id=(\d+)"
+    pattern = BASE_PATTERN + r"page=favorites&s=view&id=(\d+)"
     example = "https://gelbooru.com/index.php?page=favorites&s=view&id=12345"
 
     skip = GelbooruBase._skip_offset
@@ -284,10 +284,10 @@ class GelbooruFavoriteExtractor(GelbooruBase,
 class GelbooruPostExtractor(GelbooruBase,
                             gelbooru_v02.GelbooruV02PostExtractor):
     """Extractor for single images from gelbooru.com"""
-    pattern = (rf"{BASE_PATTERN}"
-               rf"(?=(?:[^#]+&)?page=post(?:&|#|$))"
-               rf"(?=(?:[^#]+&)?s=view(?:&|#|$))"
-               rf"(?:[^#]+&)?id=(\d+)")
+    pattern = (BASE_PATTERN +
+               r"(?=(?:[^#]+&)?page=post(?:&|#|$))"
+               r"(?=(?:[^#]+&)?s=view(?:&|#|$))"
+               r"(?:[^#]+&)?id=(\d+)")
     example = "https://gelbooru.com/index.php?page=post&s=view&id=12345"
 
 
diff --git a/gallery_dl/extractor/gelbooru_v01.py b/gallery_dl/extractor/gelbooru_v01.py
index 7b9c7328..13482721 100644
--- a/gallery_dl/extractor/gelbooru_v01.py
+++ b/gallery_dl/extractor/gelbooru_v01.py
@@ -87,7 +87,7 @@ class GelbooruV01TagExtractor(GelbooruV01Extractor):
     subcategory = "tag"
     directory_fmt = ("{category}", "{search_tags}")
     archive_fmt = "t_{search_tags}_{id}"
-    pattern = rf"{BASE_PATTERN}/index\.php\?page=post&s=list&tags=([^&#]+)"
+    pattern = BASE_PATTERN + r"/index\.php\?page=post&s=list&tags=([^&#]+)"
     example = "https://allgirl.booru.org/index.php?page=post&s=list&tags=TAG"
 
     def metadata(self):
@@ -104,7 +104,7 @@ class GelbooruV01FavoriteExtractor(GelbooruV01Extractor):
     directory_fmt = ("{category}", "favorites", "{favorite_id}")
     archive_fmt = "f_{favorite_id}_{id}"
     per_page = 50
-    pattern = rf"{BASE_PATTERN}/index\.php\?page=favorites&s=view&id=(\d+)"
+    pattern = BASE_PATTERN + r"/index\.php\?page=favorites&s=view&id=(\d+)"
     example = "https://allgirl.booru.org/index.php?page=favorites&s=view&id=1"
 
     def metadata(self):
@@ -120,7 +120,7 @@ class GelbooruV01FavoriteExtractor(GelbooruV01Extractor):
 class GelbooruV01PostExtractor(GelbooruV01Extractor):
     subcategory = "post"
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}/index\.php\?page=post&s=view&id=(\d+)"
+    pattern = BASE_PATTERN + r"/index\.php\?page=post&s=view&id=(\d+)"
     example = "https://allgirl.booru.org/index.php?page=post&s=view&id=12345"
 
     def posts(self):
diff --git a/gallery_dl/extractor/gelbooru_v02.py b/gallery_dl/extractor/gelbooru_v02.py
index 122f5a91..3a4b9208 100644
--- a/gallery_dl/extractor/gelbooru_v02.py
+++ b/gallery_dl/extractor/gelbooru_v02.py
@@ -190,7 +190,7 @@ class GelbooruV02TagExtractor(GelbooruV02Extractor):
     subcategory = "tag"
     directory_fmt = ("{category}", "{search_tags}")
     archive_fmt = "t_{search_tags}_{id}"
-    pattern = rf"{BASE_PATTERN}/index\.php\?page=post&s=list&tags=([^&#]*)"
+    pattern = BASE_PATTERN + r"/index\.php\?page=post&s=list&tags=([^&#]*)"
     example = "https://safebooru.org/index.php?page=post&s=list&tags=TAG"
 
     def posts(self):
@@ -206,7 +206,7 @@ class GelbooruV02PoolExtractor(GelbooruV02Extractor):
     subcategory = "pool"
     directory_fmt = ("{category}", "pool", "{pool}")
     archive_fmt = "p_{pool}_{id}"
-    pattern = rf"{BASE_PATTERN}/index\.php\?page=pool&s=show&id=(\d+)"
+    pattern = BASE_PATTERN + r"/index\.php\?page=pool&s=show&id=(\d+)"
     example = "https://safebooru.org/index.php?page=pool&s=show&id=12345"
 
     def __init__(self, match):
@@ -257,7 +257,7 @@ class GelbooruV02FavoriteExtractor(GelbooruV02Extractor):
     directory_fmt = ("{category}", "favorites", "{favorite_id}")
     archive_fmt = "f_{favorite_id}_{id}"
     per_page = 50
-    pattern = rf"{BASE_PATTERN}/index\.php\?page=favorites&s=view&id=(\d+)"
+    pattern = BASE_PATTERN + r"/index\.php\?page=favorites&s=view&id=(\d+)"
     example = "https://safebooru.org/index.php?page=favorites&s=view&id=12345"
 
     def metadata(self):
@@ -275,7 +275,7 @@ class GelbooruV02FavoriteExtractor(GelbooruV02Extractor):
 class GelbooruV02PostExtractor(GelbooruV02Extractor):
     subcategory = "post"
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}/index\.php\?page=post&s=view&id=(\d+)"
+    pattern = BASE_PATTERN + r"/index\.php\?page=post&s=view&id=(\d+)"
     example = "https://safebooru.org/index.php?page=post&s=view&id=12345"
 
     def posts(self):
diff --git a/gallery_dl/extractor/girlsreleased.py b/gallery_dl/extractor/girlsreleased.py
index 0fbdeffc..da1add92 100644
--- a/gallery_dl/extractor/girlsreleased.py
+++ b/gallery_dl/extractor/girlsreleased.py
@@ -22,14 +22,14 @@ class GirlsreleasedExtractor(Extractor):
 
     def items(self):
         data = {"_extractor": GirlsreleasedSetExtractor}
-        base = f"{self.root}/set/"
+        base = self.root + "/set/"
         for set in self._pagination():
-            yield Message.Queue, f"{base}{set[0]}", data
+            yield Message.Queue, base + set[0], data
 
     def _pagination(self):
         base = f"{self.root}/api/0.2/sets/{self._path}/{self.groups[0]}/page/"
         for pnum in itertools.count():
-            sets = self.request_json(f"{base}{pnum}")["sets"]
+            sets = self.request_json(base + str(pnum))["sets"]
             if not sets:
                 return
 
@@ -41,7 +41,7 @@ class GirlsreleasedExtractor(Extractor):
 class GirlsreleasedSetExtractor(GirlsreleasedExtractor):
     """Extractor for girlsreleased galleries"""
     subcategory = "set"
-    pattern = rf"{BASE_PATTERN}/set/(\d+)"
+    pattern = BASE_PATTERN + r"/set/(\d+)"
     example = "https://girlsreleased.com/set/12345"
 
     def items(self):
@@ -65,12 +65,12 @@ class GirlsreleasedSetExtractor(GirlsreleasedExtractor):
 class GirlsreleasedModelExtractor(GirlsreleasedExtractor):
     """Extractor for girlsreleased models"""
     subcategory = _path = "model"
-    pattern = rf"{BASE_PATTERN}/model/(\d+(?:/.+)?)"
+    pattern = BASE_PATTERN + r"/model/(\d+(?:/.+)?)"
     example = "https://girlsreleased.com/model/12345/MODEL"
 
 
 class GirlsreleasedSiteExtractor(GirlsreleasedExtractor):
     """Extractor for girlsreleased sites"""
     subcategory = _path = "site"
-    pattern = rf"{BASE_PATTERN}/site/([^/?#]+(?:/model/\d+/?.*)?)"
+    pattern = BASE_PATTERN + r"/site/([^/?#]+(?:/model/\d+/?.*)?)"
     example = "https://girlsreleased.com/site/SITE"
diff --git a/gallery_dl/extractor/girlswithmuscle.py b/gallery_dl/extractor/girlswithmuscle.py
index e61e472e..420b2ac8 100644
--- a/gallery_dl/extractor/girlswithmuscle.py
+++ b/gallery_dl/extractor/girlswithmuscle.py
@@ -60,7 +60,7 @@ class GirlswithmuscleExtractor(Extractor):
 class GirlswithmusclePostExtractor(GirlswithmuscleExtractor):
     """Extractor for individual posts on girlswithmuscle.com"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/(\d+)"
+    pattern = BASE_PATTERN + r"/(\d+)"
     example = "https://www.girlswithmuscle.com/12345/"
 
     def items(self):
@@ -143,7 +143,7 @@ class GirlswithmusclePostExtractor(GirlswithmuscleExtractor):
 class GirlswithmuscleSearchExtractor(GirlswithmuscleExtractor):
     """Extractor for search results on girlswithmuscle.com"""
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/images/(.*)"
+    pattern = BASE_PATTERN + r"/images/(.*)"
     example = "https://www.girlswithmuscle.com/images/?name=MODEL"
 
     def pages(self):
diff --git a/gallery_dl/extractor/hatenablog.py b/gallery_dl/extractor/hatenablog.py
index 7065d7bb..7740eda7 100644
--- a/gallery_dl/extractor/hatenablog.py
+++ b/gallery_dl/extractor/hatenablog.py
@@ -123,7 +123,7 @@ class HatenablogEntriesExtractor(HatenablogExtractor):
 class HatenablogEntryExtractor(HatenablogExtractor):
     """Extractor for a single entry URL"""
     subcategory = "entry"
-    pattern = rf"{BASE_PATTERN}/entry/([^?#]+){QUERY_RE}"
+    pattern = BASE_PATTERN + r"/entry/([^?#]+)" + QUERY_RE
     example = "https://BLOG.hatenablog.com/entry/PATH"
 
     def __init__(self, match):
@@ -146,21 +146,21 @@ class HatenablogEntryExtractor(HatenablogExtractor):
 class HatenablogHomeExtractor(HatenablogEntriesExtractor):
     """Extractor for a blog's home page"""
     subcategory = "home"
-    pattern = rf"{BASE_PATTERN}(/?){QUERY_RE}"
+    pattern = BASE_PATTERN + r"(/?)" + QUERY_RE
     example = "https://BLOG.hatenablog.com"
 
 
 class HatenablogArchiveExtractor(HatenablogEntriesExtractor):
     """Extractor for a blog's archive page"""
     subcategory = "archive"
-    pattern = (rf"{BASE_PATTERN}(/archive(?:/\d+(?:/\d+(?:/\d+)?)?"
-               rf"|/category/[^?#]+)?){QUERY_RE}")
+    pattern = (BASE_PATTERN + r"(/archive(?:/\d+(?:/\d+(?:/\d+)?)?"
+               r"|/category/[^?#]+)?)" + QUERY_RE)
     example = "https://BLOG.hatenablog.com/archive/2024"
 
 
 class HatenablogSearchExtractor(HatenablogEntriesExtractor):
     """Extractor for a blog's search results"""
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}(/search){QUERY_RE}"
+    pattern = BASE_PATTERN + r"(/search)" + QUERY_RE
     example = "https://BLOG.hatenablog.com/search?q=QUERY"
     allowed_parameters = ("q",)
diff --git a/gallery_dl/extractor/hdoujin.py b/gallery_dl/extractor/hdoujin.py
index 080b8997..927aea2b 100644
--- a/gallery_dl/extractor/hdoujin.py
+++ b/gallery_dl/extractor/hdoujin.py
@@ -23,19 +23,19 @@ class HdoujinBase():
 
 class HdoujinGalleryExtractor(
         HdoujinBase, schalenetwork.SchalenetworkGalleryExtractor):
-    pattern = rf"{BASE_PATTERN}/(?:g|reader)/(\d+)/(\w+)"
+    pattern = BASE_PATTERN + r"/(?:g|reader)/(\d+)/(\w+)"
     example = "https://hdoujin.org/g/12345/67890abcdef/"
 
 
 class HdoujinSearchExtractor(
         HdoujinBase, schalenetwork.SchalenetworkSearchExtractor):
-    pattern = rf"{BASE_PATTERN}/(?:tag/([^/?#]+)|browse)?(?:/?\?([^#]*))?$"
+    pattern = BASE_PATTERN + r"/(?:tag/([^/?#]+)|browse)?(?:/?\?([^#]*))?$"
     example = "https://hdoujin.org/browse?s=QUERY"
 
 
 class HdoujinFavoriteExtractor(
         HdoujinBase, schalenetwork.SchalenetworkFavoriteExtractor):
-    pattern = rf"{BASE_PATTERN}/favorites(?:\?([^#]*))?"
+    pattern = BASE_PATTERN + r"/favorites(?:\?([^#]*))?"
     example = "https://hdoujin.org/favorites"
 
 
diff --git a/gallery_dl/extractor/hentaicosplays.py b/gallery_dl/extractor/hentaicosplays.py
index b5f3d0e1..5c2628fa 100644
--- a/gallery_dl/extractor/hentaicosplays.py
+++ b/gallery_dl/extractor/hentaicosplays.py
@@ -38,7 +38,7 @@ class HentaicosplaysGalleryExtractor(
     directory_fmt = ("{site}", "{title}")
     filename_fmt = "{filename}.{extension}"
     archive_fmt = "{title}_{filename}"
-    pattern = rf"{BASE_PATTERN}/(?:image|story)/([\w-]+)"
+    pattern = BASE_PATTERN + r"/(?:image|story)/([\w-]+)"
     example = "https://hentai-cosplay-xxx.com/image/TITLE/"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/hentaifoundry.py b/gallery_dl/extractor/hentaifoundry.py
index 882183b9..f276ce4b 100644
--- a/gallery_dl/extractor/hentaifoundry.py
+++ b/gallery_dl/extractor/hentaifoundry.py
@@ -214,7 +214,7 @@ class HentaifoundryExtractor(Extractor):
 
 class HentaifoundryUserExtractor(Dispatch, HentaifoundryExtractor):
     """Extractor for a hentaifoundry user profile"""
-    pattern = rf"{BASE_PATTERN}/user/([^/?#]+)/profile"
+    pattern = BASE_PATTERN + r"/user/([^/?#]+)/profile"
     example = "https://www.hentai-foundry.com/user/USER/profile"
 
     def items(self):
@@ -235,7 +235,7 @@ class HentaifoundryUserExtractor(Dispatch, HentaifoundryExtractor):
 class HentaifoundryPicturesExtractor(HentaifoundryExtractor):
     """Extractor for all pictures of a hentaifoundry user"""
     subcategory = "pictures"
-    pattern = rf"{BASE_PATTERN}/pictures/user/([^/?#]+)(?:/page/(\d+))?/?$"
+    pattern = BASE_PATTERN + r"/pictures/user/([^/?#]+)(?:/page/(\d+))?/?$"
     example = "https://www.hentai-foundry.com/pictures/user/USER"
 
     def __init__(self, match):
@@ -247,7 +247,7 @@ class HentaifoundryScrapsExtractor(HentaifoundryExtractor):
     """Extractor for scraps of a hentaifoundry user"""
     subcategory = "scraps"
     directory_fmt = ("{category}", "{user}", "Scraps")
-    pattern = rf"{BASE_PATTERN}/pictures/user/([^/?#]+)/scraps"
+    pattern = BASE_PATTERN + r"/pictures/user/([^/?#]+)/scraps"
     example = "https://www.hentai-foundry.com/pictures/user/USER/scraps"
 
     def __init__(self, match):
@@ -260,7 +260,7 @@ class HentaifoundryFavoriteExtractor(HentaifoundryExtractor):
     subcategory = "favorite"
     directory_fmt = ("{category}", "{user}", "Favorites")
     archive_fmt = "f_{user}_{index}"
-    pattern = rf"{BASE_PATTERN}/user/([^/?#]+)/faves/pictures"
+    pattern = BASE_PATTERN + r"/user/([^/?#]+)/faves/pictures"
     example = "https://www.hentai-foundry.com/user/USER/faves/pictures"
 
     def __init__(self, match):
@@ -273,7 +273,7 @@ class HentaifoundryTagExtractor(HentaifoundryExtractor):
     subcategory = "tag"
     directory_fmt = ("{category}", "{search_tags}")
     archive_fmt = "t_{search_tags}_{index}"
-    pattern = rf"{BASE_PATTERN}/pictures/tagged/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/pictures/tagged/([^/?#]+)"
     example = "https://www.hentai-foundry.com/pictures/tagged/TAG"
 
     def __init__(self, match):
@@ -289,7 +289,7 @@ class HentaifoundryRecentExtractor(HentaifoundryExtractor):
     subcategory = "recent"
     directory_fmt = ("{category}", "Recent Pictures", "{date}")
     archive_fmt = "r_{index}"
-    pattern = rf"{BASE_PATTERN}/pictures/recent/(\d\d\d\d-\d\d-\d\d)"
+    pattern = BASE_PATTERN + r"/pictures/recent/(\d\d\d\d-\d\d-\d\d)"
     example = "https://www.hentai-foundry.com/pictures/recent/1970-01-01"
 
     def __init__(self, match):
@@ -305,7 +305,7 @@ class HentaifoundryPopularExtractor(HentaifoundryExtractor):
     subcategory = "popular"
     directory_fmt = ("{category}", "Popular Pictures")
     archive_fmt = "p_{index}"
-    pattern = rf"{BASE_PATTERN}/pictures/popular()"
+    pattern = BASE_PATTERN + r"/pictures/popular()"
     example = "https://www.hentai-foundry.com/pictures/popular"
 
     def __init__(self, match):
@@ -339,7 +339,7 @@ class HentaifoundryStoriesExtractor(HentaifoundryExtractor):
     """Extractor for stories of a hentaifoundry user"""
     subcategory = "stories"
     archive_fmt = "s_{index}"
-    pattern = rf"{BASE_PATTERN}/stories/user/([^/?#]+)(?:/page/(\d+))?/?$"
+    pattern = BASE_PATTERN + r"/stories/user/([^/?#]+)(?:/page/(\d+))?/?$"
     example = "https://www.hentai-foundry.com/stories/user/USER"
 
     def items(self):
@@ -358,7 +358,7 @@ class HentaifoundryStoryExtractor(HentaifoundryExtractor):
     """Extractor for a hentaifoundry story"""
     subcategory = "story"
     archive_fmt = "s_{index}"
-    pattern = rf"{BASE_PATTERN}/stories/user/([^/?#]+)/(\d+)"
+    pattern = BASE_PATTERN + r"/stories/user/([^/?#]+)/(\d+)"
     example = "https://www.hentai-foundry.com/stories/user/USER/12345/TITLE"
 
     skip = Extractor.skip
diff --git a/gallery_dl/extractor/hiperdex.py b/gallery_dl/extractor/hiperdex.py
index 0eaf798e..a07a6b51 100644
--- a/gallery_dl/extractor/hiperdex.py
+++ b/gallery_dl/extractor/hiperdex.py
@@ -67,7 +67,7 @@ class HiperdexBase():
 
 class HiperdexChapterExtractor(HiperdexBase, ChapterExtractor):
     """Extractor for hiperdex manga chapters"""
-    pattern = rf"{BASE_PATTERN}(/mangas?/([^/?#]+)/([^/?#]+))"
+    pattern = BASE_PATTERN + r"(/mangas?/([^/?#]+)/([^/?#]+))"
     example = "https://hiperdex.com/manga/MANGA/CHAPTER/"
 
     def __init__(self, match):
@@ -89,7 +89,7 @@ class HiperdexChapterExtractor(HiperdexBase, ChapterExtractor):
 class HiperdexMangaExtractor(HiperdexBase, MangaExtractor):
     """Extractor for hiperdex manga"""
     chapterclass = HiperdexChapterExtractor
-    pattern = rf"{BASE_PATTERN}(/mangas?/([^/?#]+))/?$"
+    pattern = BASE_PATTERN + r"(/mangas?/([^/?#]+))/?$"
     example = "https://hiperdex.com/manga/MANGA/"
 
     def __init__(self, match):
@@ -125,7 +125,7 @@ class HiperdexArtistExtractor(HiperdexBase, MangaExtractor):
     categorytransfer = False
     chapterclass = HiperdexMangaExtractor
     reverse = False
-    pattern = rf"{BASE_PATTERN}(/manga-a(?:rtist|uthor)/(?:[^/?#]+))"
+    pattern = BASE_PATTERN + r"(/manga-a(?:rtist|uthor)/(?:[^/?#]+))"
     example = "https://hiperdex.com/manga-artist/NAME/"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/hitomi.py b/gallery_dl/extractor/hitomi.py
index b05a9a7b..fd3d00ed 100644
--- a/gallery_dl/extractor/hitomi.py
+++ b/gallery_dl/extractor/hitomi.py
@@ -32,14 +32,14 @@ class HitomiExtractor(Extractor):
             language = tag
             tag = "index"
         else:
-            ns = f"{ns}/"
+            ns += "/"
 
         url = (f"https://ltn.{self.domain}/n/{ns}"
                f"/{tag.replace('_', ' ')}-{language}.nozomi")
         if headers is None:
             headers = {}
         headers["Origin"] = self.root
-        headers["Referer"] = f"{self.root}/"
+        headers["Referer"] = self.root + "/"
         return decode_nozomi(self.request(url, headers=headers).content)
 
 
diff --git a/gallery_dl/extractor/hotleak.py b/gallery_dl/extractor/hotleak.py
index 953cf4e0..600984e9 100644
--- a/gallery_dl/extractor/hotleak.py
+++ b/gallery_dl/extractor/hotleak.py
@@ -61,7 +61,7 @@ def decode_video_url(url):
 class HotleakPostExtractor(HotleakExtractor):
     """Extractor for individual posts on hotleak"""
     subcategory = "post"
-    pattern = (rf"{BASE_PATTERN}/(?!(?:hot|creators|videos|photos)(?:$|/))"
+    pattern = (BASE_PATTERN + r"/(?!(?:hot|creators|videos|photos)(?:$|/))"
                r"([^/]+)/(photo|video)/(\d+)")
     example = "https://hotleak.vip/MODEL/photo/12345"
 
@@ -96,7 +96,7 @@ class HotleakPostExtractor(HotleakExtractor):
 class HotleakCreatorExtractor(HotleakExtractor):
     """Extractor for all posts from a hotleak creator"""
     subcategory = "creator"
-    pattern = (rf"{BASE_PATTERN}/(?!(?:hot|creators|videos|photos)(?:$|/))"
+    pattern = (BASE_PATTERN + r"/(?!(?:hot|creators|videos|photos)(?:$|/))"
                r"([^/?#]+)/?$")
     example = "https://hotleak.vip/MODEL"
 
@@ -150,7 +150,7 @@ class HotleakCreatorExtractor(HotleakExtractor):
 class HotleakCategoryExtractor(HotleakExtractor):
     """Extractor for hotleak categories"""
     subcategory = "category"
-    pattern = rf"{BASE_PATTERN}/(hot|creators|videos|photos)(?:/?\?([^#]+))?"
+    pattern = BASE_PATTERN + r"/(hot|creators|videos|photos)(?:/?\?([^#]+))?"
     example = "https://hotleak.vip/photos"
 
     def __init__(self, match):
@@ -172,7 +172,7 @@ class HotleakCategoryExtractor(HotleakExtractor):
 class HotleakSearchExtractor(HotleakExtractor):
     """Extractor for hotleak search results"""
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/search(?:/?\?([^#]+))"
+    pattern = BASE_PATTERN + r"/search(?:/?\?([^#]+))"
     example = "https://hotleak.vip/search?search=QUERY"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/idolcomplex.py b/gallery_dl/extractor/idolcomplex.py
index a8f1298f..2f388024 100644
--- a/gallery_dl/extractor/idolcomplex.py
+++ b/gallery_dl/extractor/idolcomplex.py
@@ -29,17 +29,17 @@ class IdolcomplexBase():
 
 class IdolcomplexTagExtractor(IdolcomplexBase, sankaku.SankakuTagExtractor):
     """Extractor for idolcomplex tag searches"""
-    pattern = rf"{BASE_PATTERN}(?:/posts)?/?\?([^#]*)"
+    pattern = BASE_PATTERN + r"(?:/posts)?/?\?([^#]*)"
     example = "https://www.idolcomplex.com/en/posts?tags=TAGS"
 
 
 class IdolcomplexPoolExtractor(IdolcomplexBase, sankaku.SankakuPoolExtractor):
     """Extractor for idolcomplex pools"""
-    pattern = rf"{BASE_PATTERN}/pools?/(?:show/)?(\w+)"
+    pattern = BASE_PATTERN + r"/pools?/(?:show/)?(\w+)"
     example = "https://www.idolcomplex.com/en/pools/0123456789abcdef"
 
 
 class IdolcomplexPostExtractor(IdolcomplexBase, sankaku.SankakuPostExtractor):
     """Extractor for individual idolcomplex posts"""
-    pattern = rf"{BASE_PATTERN}/posts?(?:/show)?/(\w+)"
+    pattern = BASE_PATTERN + r"/posts?(?:/show)?/(\w+)"
     example = "https://www.idolcomplex.com/en/posts/0123456789abcdef"
diff --git a/gallery_dl/extractor/imagechest.py b/gallery_dl/extractor/imagechest.py
index 074b4ae1..2191958d 100644
--- a/gallery_dl/extractor/imagechest.py
+++ b/gallery_dl/extractor/imagechest.py
@@ -19,7 +19,7 @@ class ImagechestGalleryExtractor(GalleryExtractor):
     """Extractor for image galleries from imgchest.com"""
     category = "imagechest"
     root = "https://imgchest.com"
-    pattern = rf"{BASE_PATTERN}/p/([A-Za-z0-9]{{11}})"
+    pattern = BASE_PATTERN + r"/p/([A-Za-z0-9]{11})"
     example = "https://imgchest.com/p/abcdefghijk"
 
     def __init__(self, match):
@@ -78,7 +78,7 @@ class ImagechestUserExtractor(Extractor):
     category = "imagechest"
     subcategory = "user"
     root = "https://imgchest.com"
-    pattern = rf"{BASE_PATTERN}/u/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/u/([^/?#]+)"
     example = "https://imgchest.com/u/USER"
 
     def items(self):
diff --git a/gallery_dl/extractor/imagefap.py b/gallery_dl/extractor/imagefap.py
index f7279694..06848e56 100644
--- a/gallery_dl/extractor/imagefap.py
+++ b/gallery_dl/extractor/imagefap.py
@@ -39,7 +39,7 @@ class ImagefapExtractor(Extractor):
 class ImagefapGalleryExtractor(ImagefapExtractor):
     """Extractor for image galleries from imagefap.com"""
     subcategory = "gallery"
-    pattern = rf"{BASE_PATTERN}/(?:gallery\.php\?gid=|gallery/|pictures/)(\d+)"
+    pattern = BASE_PATTERN + r"/(?:gallery\.php\?gid=|gallery/|pictures/)(\d+)"
     example = "https://www.imagefap.com/gallery/12345"
 
     def __init__(self, match):
@@ -110,7 +110,7 @@ class ImagefapGalleryExtractor(ImagefapExtractor):
 class ImagefapImageExtractor(ImagefapExtractor):
     """Extractor for single images from imagefap.com"""
     subcategory = "image"
-    pattern = rf"{BASE_PATTERN}/photo/(\d+)"
+    pattern = BASE_PATTERN + r"/photo/(\d+)"
     example = "https://www.imagefap.com/photo/12345"
 
     def __init__(self, match):
@@ -148,9 +148,9 @@ class ImagefapImageExtractor(ImagefapExtractor):
 class ImagefapFolderExtractor(ImagefapExtractor):
     """Extractor for imagefap user folders"""
     subcategory = "folder"
-    pattern = (rf"{BASE_PATTERN}/(?:organizer/|"
-               rf"(?:usergallery\.php\?user(id)?=([^&#]+)&"
-               rf"|profile/([^/?#]+)/galleries\?)folderid=)(\d+|-1)")
+    pattern = (BASE_PATTERN + r"/(?:organizer/|"
+               r"(?:usergallery\.php\?user(id)?=([^&#]+)&"
+               r"|profile/([^/?#]+)/galleries\?)folderid=)(\d+|-1)")
     example = "https://www.imagefap.com/organizer/12345"
 
     def __init__(self, match):
@@ -206,9 +206,9 @@ class ImagefapFolderExtractor(ImagefapExtractor):
 class ImagefapUserExtractor(ImagefapExtractor):
     """Extractor for an imagefap user profile"""
     subcategory = "user"
-    pattern = (rf"{BASE_PATTERN}/(?:"
-               rf"profile(?:\.php\?user=|/)([^/?#]+)(?:/galleries)?|"
-               rf"usergallery\.php\?userid=(\d+))(?:$|#)")
+    pattern = (BASE_PATTERN +
+               r"/(?:profile(?:\.php\?user=|/)([^/?#]+)(?:/galleries)?"
+               r"|usergallery\.php\?userid=(\d+))(?:$|#)")
     example = "https://www.imagefap.com/profile/USER"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/imagehosts.py b/gallery_dl/extractor/imagehosts.py
index 21e6cf8d..47dbc0f9 100644
--- a/gallery_dl/extractor/imagehosts.py
+++ b/gallery_dl/extractor/imagehosts.py
@@ -28,10 +28,7 @@ class ImagehostImageExtractor(Extractor):
 
     def __init__(self, match):
         Extractor.__init__(self, match)
-        if self.root:
-            self.page_url = f"{self.root}{match[1]}"
-        else:
-            self.page_url = f"http{'s' if self._https else ''}://{match[1]}"
+        self.page_url = (self.root or "https://") + match[1]
         self.token = match[2]
 
         if self._params == "simple":
@@ -461,8 +458,8 @@ class ImgdriveImageExtractor(ImagehostImageExtractor):
 
     def __init__(self, match):
         path, category, self.token = match.groups()
-        self.page_url = f"https://{path}"
-        self.category = f"img{category}"
+        self.page_url = "https://" + path
+        self.category = "img" + category
         Extractor.__init__(self, match)
 
     def get_info(self, page):
diff --git a/gallery_dl/extractor/imgbb.py b/gallery_dl/extractor/imgbb.py
index d9573288..ed06c1ca 100644
--- a/gallery_dl/extractor/imgbb.py
+++ b/gallery_dl/extractor/imgbb.py
@@ -136,8 +136,8 @@ class ImgbbAlbumExtractor(ImgbbExtractor):
                 'data-text="image-count">', "<")),
         }
 
-        url = f"{self.root}/json"
-        params["pathname"] = f"/album/{album['id']}"
+        url = self.root + "/json"
+        params["pathname"] = "/album/" + album["id"]
         return self._pagination(page, url, params)
 
 
@@ -190,11 +190,11 @@ class ImgbbUserExtractor(ImgbbExtractor):
 
         if response.status_code < 300:
             params["pathname"] = "/"
-            return self._pagination(response.text, f"{url}json", params)
+            return self._pagination(response.text, url + "json", params)
 
         if response.status_code == 301:
             raise exception.NotFoundError("user")
-        redirect = f"HTTP redirect to {response.headers.get('Location')}"
+        redirect = "HTTP redirect to " + response.headers.get("Location", "")
         if response.status_code == 302:
             raise exception.AuthRequired(
                 ("username & password", "authenticated cookies"),
diff --git a/gallery_dl/extractor/imgpile.py b/gallery_dl/extractor/imgpile.py
index f6342038..c73926ac 100644
--- a/gallery_dl/extractor/imgpile.py
+++ b/gallery_dl/extractor/imgpile.py
@@ -22,13 +22,10 @@ class ImgpileExtractor(Extractor):
                      "{post[title]} ({post[id_slug]})")
     archive_fmt = "{post[id_slug]}_{id}"
 
-    def items(self):
-        pass
-
 
 class ImgpilePostExtractor(ImgpileExtractor):
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/p/(\w+)"
+    pattern = BASE_PATTERN + r"/p/(\w+)"
     example = "https://imgpile.com/p/AbCdEfG"
 
     def items(self):
@@ -71,24 +68,23 @@ class ImgpilePostExtractor(ImgpileExtractor):
                 "id_slug": text.extr(media, 'data-id="', '"'),
                 "id" : text.parse_int(text.extr(
                     media, 'data-media-id="', '"')),
-                "url": f"""http{text.extr(media, '<a href="http', '"')}""",
+                "url": "http" + text.extr(media, '<a href="http', '"'),
             })
         return files
 
 
 class ImgpileUserExtractor(ImgpileExtractor):
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/u/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/u/([^/?#]+)"
     example = "https://imgpile.com/u/USER"
 
     def items(self):
-        url = f"{self.root}/api/v1/posts"
+        url = self.root + "/api/v1/posts"
         params = {
             "limit"     : "100",
             "sort"      : "latest",
             "period"    : "all",
             "visibility": "public",
-            #  "moderation_status": "approved",
             "username"  : self.groups[0],
         }
         headers = {
@@ -101,7 +97,7 @@ class ImgpileUserExtractor(ImgpileExtractor):
             "Sec-Fetch-Site": "same-origin",
         }
 
-        base = f"{self.root}/p/"
+        base = self.root + "/p/"
         while True:
             data = self.request_json(url, params=params, headers=headers)
 
@@ -111,7 +107,7 @@ class ImgpileUserExtractor(ImgpileExtractor):
 
             for item in data["data"]:
                 item["_extractor"] = ImgpilePostExtractor
-                url = f"{base}{item['slug']}"
+                url = base + item["slug"]
                 yield Message.Queue, url, item
 
             url = data["links"].get("next")
diff --git a/gallery_dl/extractor/imgur.py b/gallery_dl/extractor/imgur.py
index 47553887..d80caf60 100644
--- a/gallery_dl/extractor/imgur.py
+++ b/gallery_dl/extractor/imgur.py
@@ -67,7 +67,7 @@ class ImgurImageExtractor(ImgurExtractor):
     subcategory = "image"
     filename_fmt = "{category}_{id}{title:?_//}.{extension}"
     archive_fmt = "{id}"
-    pattern = (rf"{BASE_PATTERN}/(?!gallery|search)"
+    pattern = (BASE_PATTERN + r"/(?!gallery|search)"
                r"(?:r/\w+/)?(?:[^/?#]+-)?(\w{7}|\w{5})[sbtmlh]?")
     example = "https://imgur.com/abcdefg"
 
@@ -93,7 +93,7 @@ class ImgurAlbumExtractor(ImgurExtractor):
     directory_fmt = ("{category}", "{album[id]}{album[title]:? - //}")
     filename_fmt = "{category}_{album[id]}_{num:>03}_{id}.{extension}"
     archive_fmt = "{album[id]}_{id}"
-    pattern = rf"{BASE_PATTERN}/a/(?:[^/?#]+-)?(\w{{7}}|\w{{5}})"
+    pattern = BASE_PATTERN + r"/a/(?:[^/?#]+-)?(\w{7}|\w{5})"
     example = "https://imgur.com/a/abcde"
 
     def items(self):
@@ -126,8 +126,7 @@ class ImgurAlbumExtractor(ImgurExtractor):
 class ImgurGalleryExtractor(ImgurExtractor):
     """Extractor for imgur galleries"""
     subcategory = "gallery"
-    pattern = (rf"{BASE_PATTERN}/"
-               rf"(?:gallery|t/\w+)/(?:[^/?#]+-)?(\w{{7}}|\w{{5}})")
+    pattern = BASE_PATTERN + r"/(?:gallery|t/\w+)/(?:[^/?#]+-)?(\w{7}|\w{5})"
     example = "https://imgur.com/gallery/abcde"
 
     def items(self):
@@ -143,7 +142,7 @@ class ImgurGalleryExtractor(ImgurExtractor):
 class ImgurUserExtractor(ImgurExtractor):
     """Extractor for all images posted by a user"""
     subcategory = "user"
-    pattern = (rf"{BASE_PATTERN}/user/(?!me(?:/|$|\?|#))"
+    pattern = (BASE_PATTERN + r"/user/(?!me(?:/|$|\?|#))"
                r"([^/?#]+)(?:/posts|/submitted)?/?$")
     example = "https://imgur.com/user/USER"
 
@@ -154,7 +153,7 @@ class ImgurUserExtractor(ImgurExtractor):
 class ImgurFavoriteExtractor(ImgurExtractor):
     """Extractor for a user's favorites"""
     subcategory = "favorite"
-    pattern = rf"{BASE_PATTERN}/user/([^/?#]+)/favorites/?$"
+    pattern = BASE_PATTERN + r"/user/([^/?#]+)/favorites/?$"
     example = "https://imgur.com/user/USER/favorites"
 
     def items(self):
@@ -164,7 +163,7 @@ class ImgurFavoriteExtractor(ImgurExtractor):
 class ImgurFavoriteFolderExtractor(ImgurExtractor):
     """Extractor for a user's favorites folder"""
     subcategory = "favorite-folder"
-    pattern = rf"{BASE_PATTERN}/user/([^/?#]+)/favorites/folder/(\d+)"
+    pattern = BASE_PATTERN + r"/user/([^/?#]+)/favorites/folder/(\d+)"
     example = "https://imgur.com/user/USER/favorites/folder/12345/TITLE"
 
     def __init__(self, match):
@@ -179,7 +178,7 @@ class ImgurFavoriteFolderExtractor(ImgurExtractor):
 class ImgurMeExtractor(ImgurExtractor):
     """Extractor for your personal uploads"""
     subcategory = "me"
-    pattern = rf"{BASE_PATTERN}/user/me(?:/posts)?(/hidden)?"
+    pattern = BASE_PATTERN + r"/user/me(?:/posts)?(/hidden)?"
     example = "https://imgur.com/user/me"
 
     def items(self):
@@ -196,7 +195,7 @@ class ImgurMeExtractor(ImgurExtractor):
 class ImgurSubredditExtractor(ImgurExtractor):
     """Extractor for a subreddits's imgur links"""
     subcategory = "subreddit"
-    pattern = rf"{BASE_PATTERN}/r/([^/?#]+)/?$"
+    pattern = BASE_PATTERN + r"/r/([^/?#]+)/?$"
     example = "https://imgur.com/r/SUBREDDIT"
 
     def items(self):
@@ -206,7 +205,7 @@ class ImgurSubredditExtractor(ImgurExtractor):
 class ImgurTagExtractor(ImgurExtractor):
     """Extractor for imgur tag searches"""
     subcategory = "tag"
-    pattern = rf"{BASE_PATTERN}/t/([^/?#]+)$"
+    pattern = BASE_PATTERN + r"/t/([^/?#]+)$"
     example = "https://imgur.com/t/TAG"
 
     def items(self):
@@ -216,7 +215,7 @@ class ImgurTagExtractor(ImgurExtractor):
 class ImgurSearchExtractor(ImgurExtractor):
     """Extractor for imgur search results"""
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/search(?:/[^?#]+)?/?\?q=([^&#]+)"
+    pattern = BASE_PATTERN + r"/search(?:/[^?#]+)?/?\?q=([^&#]+)"
     example = "https://imgur.com/search?q=UERY"
 
     def items(self):
@@ -270,11 +269,11 @@ class ImgurAPI():
         return self._pagination(endpoint, params)
 
     def gallery_subreddit(self, subreddit):
-        endpoint = f"/3/gallery/r/{subreddit}"
+        endpoint = "/3/gallery/r/" + subreddit
         return self._pagination(endpoint)
 
     def gallery_tag(self, tag):
-        endpoint = f"/3/gallery/t/{tag}"
+        endpoint = "/3/gallery/t/" + tag
         return self._pagination(endpoint, key="items")
 
     def image(self, image_hash):
diff --git a/gallery_dl/extractor/imhentai.py b/gallery_dl/extractor/imhentai.py
index d83dcc8e..c996fb81 100644
--- a/gallery_dl/extractor/imhentai.py
+++ b/gallery_dl/extractor/imhentai.py
@@ -79,7 +79,7 @@ BASE_PATTERN = ImhentaiExtractor.update({
 
 class ImhentaiGalleryExtractor(ImhentaiExtractor, GalleryExtractor):
     """Extractor for imhentai galleries"""
-    pattern = rf"{BASE_PATTERN}/(?:gallery|view)/(\d+)"
+    pattern = BASE_PATTERN + r"/(?:gallery|view)/(\d+)"
     example = "https://imhentai.xxx/gallery/12345/"
 
     def __init__(self, match):
@@ -141,7 +141,7 @@ class ImhentaiGalleryExtractor(ImhentaiExtractor, GalleryExtractor):
 class ImhentaiTagExtractor(ImhentaiExtractor):
     """Extractor for imhentai tag searches"""
     subcategory = "tag"
-    pattern = (rf"{BASE_PATTERN}(/(?:"
+    pattern = (BASE_PATTERN + r"(/(?:"
                r"artist|category|character|group|language|parody|tag"
                r")/([^/?#]+))")
     example = "https://imhentai.xxx/tag/TAG/"
@@ -154,7 +154,7 @@ class ImhentaiTagExtractor(ImhentaiExtractor):
 class ImhentaiSearchExtractor(ImhentaiExtractor):
     """Extractor for imhentai search results"""
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}(/(?:advanced-)?search/?\?[^#]+|/[^/?#]+/?)"
+    pattern = BASE_PATTERN + r"(/(?:advanced-)?search/?\?[^#]+|/[^/?#]+/?)"
     example = "https://imhentai.xxx/search/?key=QUERY"
 
     def items(self):
diff --git a/gallery_dl/extractor/inkbunny.py b/gallery_dl/extractor/inkbunny.py
index 547d4eea..4158891d 100644
--- a/gallery_dl/extractor/inkbunny.py
+++ b/gallery_dl/extractor/inkbunny.py
@@ -71,7 +71,7 @@ class InkbunnyExtractor(Extractor):
 class InkbunnyUserExtractor(InkbunnyExtractor):
     """Extractor for inkbunny user profiles"""
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/(?!s/)(gallery/|scraps/)?(\w+)(?:$|[/?#])"
+    pattern = BASE_PATTERN + r"/(?!s/)(gallery/|scraps/)?(\w+)(?:$|[/?#])"
     example = "https://inkbunny.net/USER"
 
     def __init__(self, match):
@@ -101,7 +101,7 @@ class InkbunnyUserExtractor(InkbunnyExtractor):
 class InkbunnyPoolExtractor(InkbunnyExtractor):
     """Extractor for inkbunny pools"""
     subcategory = "pool"
-    pattern = (rf"{BASE_PATTERN}/(?:"
+    pattern = (BASE_PATTERN + r"/(?:"
                r"poolview_process\.php\?pool_id=(\d+)|"
                r"submissionsviewall\.php"
                r"\?((?:[^#]+&)?mode=pool(?:&[^#]+)?))")
@@ -132,7 +132,7 @@ class InkbunnyFavoriteExtractor(InkbunnyExtractor):
     """Extractor for inkbunny user favorites"""
     subcategory = "favorite"
     directory_fmt = ("{category}", "{favs_username!l}", "Favorites")
-    pattern = (rf"{BASE_PATTERN}/(?:"
+    pattern = (BASE_PATTERN + r"/(?:"
                r"userfavorites_process\.php\?favs_user_id=(\d+)|"
                r"submissionsviewall\.php"
                r"\?((?:[^#]+&)?mode=userfavs(?:&[^#]+)?))")
@@ -175,7 +175,7 @@ class InkbunnyFavoriteExtractor(InkbunnyExtractor):
 class InkbunnyUnreadExtractor(InkbunnyExtractor):
     """Extractor for unread inkbunny submissions"""
     subcategory = "unread"
-    pattern = (rf"{BASE_PATTERN}/submissionsviewall\.php"
+    pattern = (BASE_PATTERN + r"/submissionsviewall\.php"
                r"\?((?:[^#]+&)?mode=unreadsubs(?:&[^#]+)?)")
     example = ("https://inkbunny.net/submissionsviewall.php"
                "?text=&mode=unreadsubs&type=")
@@ -195,7 +195,7 @@ class InkbunnyUnreadExtractor(InkbunnyExtractor):
 class InkbunnySearchExtractor(InkbunnyExtractor):
     """Extractor for inkbunny search results"""
     subcategory = "search"
-    pattern = (rf"{BASE_PATTERN}/submissionsviewall\.php"
+    pattern = (BASE_PATTERN + r"/submissionsviewall\.php"
                r"\?((?:[^#]+&)?mode=search(?:&[^#]+)?)")
     example = ("https://inkbunny.net/submissionsviewall.php"
                "?text=TAG&mode=search&type=")
@@ -229,7 +229,7 @@ class InkbunnySearchExtractor(InkbunnyExtractor):
 class InkbunnyFollowingExtractor(InkbunnyExtractor):
     """Extractor for inkbunny user watches"""
     subcategory = "following"
-    pattern = (rf"{BASE_PATTERN}/(?:"
+    pattern = (BASE_PATTERN + r"/(?:"
                r"watchlist_process\.php\?mode=watching&user_id=(\d+)|"
                r"usersviewall\.php"
                r"\?((?:[^#]+&)?mode=watching(?:&[^#]+)?))")
@@ -268,7 +268,7 @@ class InkbunnyFollowingExtractor(InkbunnyExtractor):
 class InkbunnyPostExtractor(InkbunnyExtractor):
     """Extractor for individual Inkbunny posts"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/s/(\d+)"
+    pattern = BASE_PATTERN + r"/s/(\d+)"
     example = "https://inkbunny.net/s/12345"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/instagram.py b/gallery_dl/extractor/instagram.py
index b89369f8..3eb33473 100644
--- a/gallery_dl/extractor/instagram.py
+++ b/gallery_dl/extractor/instagram.py
@@ -16,7 +16,7 @@ import itertools
 import binascii
 
 BASE_PATTERN = r"(?:https?://)?(?:www\.)?instagram\.com"
-USER_PATTERN = rf"{BASE_PATTERN}/(?!(?:p|tv|reel|explore|stories)/)([^/?#]+)"
+USER_PATTERN = BASE_PATTERN + r"/(?!(?:p|tv|reel|explore|stories)/)([^/?#]+)"
 
 
 class InstagramExtractor(Extractor):
@@ -505,7 +505,7 @@ class InstagramPostExtractor(InstagramExtractor):
 
 class InstagramUserExtractor(Dispatch, InstagramExtractor):
     """Extractor for an Instagram user profile"""
-    pattern = rf"{USER_PATTERN}/?(?:$|[?#])"
+    pattern = USER_PATTERN + r"/?(?:$|[?#])"
     example = "https://www.instagram.com/USER/"
 
     def items(self):
@@ -525,7 +525,7 @@ class InstagramUserExtractor(Dispatch, InstagramExtractor):
 class InstagramPostsExtractor(InstagramExtractor):
     """Extractor for an Instagram user's posts"""
     subcategory = "posts"
-    pattern = rf"{USER_PATTERN}/posts"
+    pattern = USER_PATTERN + r"/posts"
     example = "https://www.instagram.com/USER/posts/"
 
     def posts(self):
@@ -542,7 +542,7 @@ class InstagramPostsExtractor(InstagramExtractor):
 class InstagramReelsExtractor(InstagramExtractor):
     """Extractor for an Instagram user's reels"""
     subcategory = "reels"
-    pattern = rf"{USER_PATTERN}/reels"
+    pattern = USER_PATTERN + r"/reels"
     example = "https://www.instagram.com/USER/reels/"
 
     def posts(self):
@@ -559,7 +559,7 @@ class InstagramReelsExtractor(InstagramExtractor):
 class InstagramTaggedExtractor(InstagramExtractor):
     """Extractor for an Instagram user's tagged posts"""
     subcategory = "tagged"
-    pattern = rf"{USER_PATTERN}/tagged"
+    pattern = USER_PATTERN + r"/tagged"
     example = "https://www.instagram.com/USER/tagged/"
 
     def metadata(self):
@@ -585,7 +585,7 @@ class InstagramTaggedExtractor(InstagramExtractor):
 class InstagramGuideExtractor(InstagramExtractor):
     """Extractor for an Instagram guide"""
     subcategory = "guide"
-    pattern = rf"{USER_PATTERN}/guide/[^/?#]+/(\d+)"
+    pattern = USER_PATTERN + r"/guide/[^/?#]+/(\d+)"
     example = "https://www.instagram.com/USER/guide/NAME/12345"
 
     def __init__(self, match):
@@ -602,7 +602,7 @@ class InstagramGuideExtractor(InstagramExtractor):
 class InstagramSavedExtractor(InstagramExtractor):
     """Extractor for an Instagram user's saved media"""
     subcategory = "saved"
-    pattern = rf"{USER_PATTERN}/saved(?:/all-posts)?/?$"
+    pattern = USER_PATTERN + r"/saved(?:/all-posts)?/?$"
     example = "https://www.instagram.com/USER/saved/"
 
     def posts(self):
@@ -612,7 +612,7 @@ class InstagramSavedExtractor(InstagramExtractor):
 class InstagramCollectionExtractor(InstagramExtractor):
     """Extractor for Instagram collection"""
     subcategory = "collection"
-    pattern = rf"{USER_PATTERN}/saved/([^/?#]+)/([^/?#]+)"
+    pattern = USER_PATTERN + r"/saved/([^/?#]+)/([^/?#]+)"
     example = "https://www.instagram.com/USER/saved/COLLECTION/12345"
 
     def __init__(self, match):
@@ -632,11 +632,11 @@ class InstagramCollectionExtractor(InstagramExtractor):
 class InstagramStoriesTrayExtractor(InstagramExtractor):
     """Extractor for your Instagram account's stories tray"""
     subcategory = "stories-tray"
-    pattern = rf"{BASE_PATTERN}/stories/me/?$()"
+    pattern = BASE_PATTERN + r"/stories/me/?$()"
     example = "https://www.instagram.com/stories/me/"
 
     def items(self):
-        base = f"{self.root}/stories/id:"
+        base = self.root + "/stories/id:"
         for story in self.api.reels_tray():
             story["date"] = self.parse_timestamp(story["latest_reel_media"])
             story["_extractor"] = InstagramStoriesExtractor
@@ -696,7 +696,7 @@ class InstagramStoriesExtractor(InstagramExtractor):
 class InstagramHighlightsExtractor(InstagramExtractor):
     """Extractor for an Instagram user's story highlights"""
     subcategory = "highlights"
-    pattern = rf"{USER_PATTERN}/highlights"
+    pattern = USER_PATTERN + r"/highlights"
     example = "https://www.instagram.com/USER/highlights/"
 
     def posts(self):
@@ -707,7 +707,7 @@ class InstagramHighlightsExtractor(InstagramExtractor):
 class InstagramFollowersExtractor(InstagramExtractor):
     """Extractor for an Instagram user's followers"""
     subcategory = "followers"
-    pattern = rf"{USER_PATTERN}/followers"
+    pattern = USER_PATTERN + r"/followers"
     example = "https://www.instagram.com/USER/followers/"
 
     def items(self):
@@ -721,7 +721,7 @@ class InstagramFollowersExtractor(InstagramExtractor):
 class InstagramFollowingExtractor(InstagramExtractor):
     """Extractor for an Instagram user's followed users"""
     subcategory = "following"
-    pattern = rf"{USER_PATTERN}/following"
+    pattern = USER_PATTERN + r"/following"
     example = "https://www.instagram.com/USER/following/"
 
     def items(self):
@@ -736,7 +736,7 @@ class InstagramTagExtractor(InstagramExtractor):
     """Extractor for Instagram tags"""
     subcategory = "tag"
     directory_fmt = ("{category}", "{subcategory}", "{tag}")
-    pattern = rf"{BASE_PATTERN}/explore/tags/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/explore/tags/([^/?#]+)"
     example = "https://www.instagram.com/explore/tags/TAG/"
 
     def metadata(self):
@@ -749,7 +749,7 @@ class InstagramTagExtractor(InstagramExtractor):
 class InstagramInfoExtractor(InstagramExtractor):
     """Extractor for an Instagram user's profile data"""
     subcategory = "info"
-    pattern = rf"{USER_PATTERN}/info"
+    pattern = USER_PATTERN + r"/info"
     example = "https://www.instagram.com/USER/info/"
 
     def items(self):
@@ -765,7 +765,7 @@ class InstagramInfoExtractor(InstagramExtractor):
 class InstagramAvatarExtractor(InstagramExtractor):
     """Extractor for an Instagram user's avatar"""
     subcategory = "avatar"
-    pattern = rf"{USER_PATTERN}/avatar"
+    pattern = USER_PATTERN + r"/avatar"
     example = "https://www.instagram.com/USER/avatar/"
 
     def posts(self):
diff --git a/gallery_dl/extractor/itaku.py b/gallery_dl/extractor/itaku.py
index 566ee8b6..5e0afb32 100644
--- a/gallery_dl/extractor/itaku.py
+++ b/gallery_dl/extractor/itaku.py
@@ -13,7 +13,7 @@ from ..cache import memcache
 from .. import text, util
 
 BASE_PATTERN = r"(?:https?://)?itaku\.ee"
-USER_PATTERN = rf"{BASE_PATTERN}/profile/([^/?#]+)"
+USER_PATTERN = BASE_PATTERN + r"/profile/([^/?#]+)"
 
 
 class ItakuExtractor(Extractor):
@@ -34,7 +34,7 @@ class ItakuExtractor(Extractor):
             for image in images:
                 image["date"] = self.parse_datetime_iso(image["date_added"])
                 for category, tags in image.pop("categorized_tags").items():
-                    image[f"tags_{category.lower()}"] = [
+                    image["tags_" + category.lower()] = [
                         t["name"] for t in tags]
                 image["tags"] = [t["name"] for t in image["tags"]]
 
@@ -73,9 +73,9 @@ class ItakuExtractor(Extractor):
             return
 
         if users := self.users():
-            base = f"{self.root}/profile/"
+            base = self.root + "/profile/"
             for user in users:
-                url = f"{base}{user['owner_username']}"
+                url = base + user["owner_username"]
                 user["_extractor"] = ItakuUserExtractor
                 yield Message.Queue, url, user
             return
@@ -86,7 +86,7 @@ class ItakuExtractor(Extractor):
 class ItakuGalleryExtractor(ItakuExtractor):
     """Extractor for an itaku user's gallery"""
     subcategory = "gallery"
-    pattern = rf"{USER_PATTERN}/gallery(?:/(\d+))?"
+    pattern = USER_PATTERN + r"/gallery(?:/(\d+))?"
     example = "https://itaku.ee/profile/USER/gallery"
 
     def images(self):
@@ -104,7 +104,7 @@ class ItakuPostsExtractor(ItakuExtractor):
                      "{id}{title:? //}")
     filename_fmt = "{file[id]}{file[title]:? //}.{extension}"
     archive_fmt = "{id}_{file[id]}"
-    pattern = rf"{USER_PATTERN}/posts(?:/(\d+))?"
+    pattern = USER_PATTERN + r"/posts(?:/(\d+))?"
     example = "https://itaku.ee/profile/USER/posts"
 
     def posts(self):
@@ -118,7 +118,7 @@ class ItakuPostsExtractor(ItakuExtractor):
 class ItakuStarsExtractor(ItakuExtractor):
     """Extractor for an itaku user's starred images"""
     subcategory = "stars"
-    pattern = rf"{USER_PATTERN}/stars(?:/(\d+))?"
+    pattern = USER_PATTERN + r"/stars(?:/(\d+))?"
     example = "https://itaku.ee/profile/USER/stars"
 
     def images(self):
@@ -132,7 +132,7 @@ class ItakuStarsExtractor(ItakuExtractor):
 
 class ItakuFollowingExtractor(ItakuExtractor):
     subcategory = "following"
-    pattern = rf"{USER_PATTERN}/following"
+    pattern = USER_PATTERN + r"/following"
     example = "https://itaku.ee/profile/USER/following"
 
     def users(self):
@@ -143,7 +143,7 @@ class ItakuFollowingExtractor(ItakuExtractor):
 
 class ItakuFollowersExtractor(ItakuExtractor):
     subcategory = "followers"
-    pattern = rf"{USER_PATTERN}/followers"
+    pattern = USER_PATTERN + r"/followers"
     example = "https://itaku.ee/profile/USER/followers"
 
     def users(self):
@@ -155,7 +155,7 @@ class ItakuFollowersExtractor(ItakuExtractor):
 class ItakuBookmarksExtractor(ItakuExtractor):
     """Extractor for an itaku bookmarks folder"""
     subcategory = "bookmarks"
-    pattern = rf"{USER_PATTERN}/bookmarks/(image|user)/(\d+)"
+    pattern = USER_PATTERN + r"/bookmarks/(image|user)/(\d+)"
     example = "https://itaku.ee/profile/USER/bookmarks/image/12345"
 
     def _init(self):
@@ -176,23 +176,23 @@ class ItakuBookmarksExtractor(ItakuExtractor):
 
 class ItakuUserExtractor(Dispatch, ItakuExtractor):
     """Extractor for itaku user profiles"""
-    pattern = rf"{USER_PATTERN}/?(?:$|\?|#)"
+    pattern = USER_PATTERN + r"/?(?:$|\?|#)"
     example = "https://itaku.ee/profile/USER"
 
     def items(self):
         base = f"{self.root}/profile/{self.groups[0]}/"
         return self._dispatch_extractors((
-            (ItakuGalleryExtractor  , f"{base}gallery"),
-            (ItakuPostsExtractor    , f"{base}posts"),
-            (ItakuFollowersExtractor, f"{base}followers"),
-            (ItakuFollowingExtractor, f"{base}following"),
-            (ItakuStarsExtractor    , f"{base}stars"),
+            (ItakuGalleryExtractor  , base + "gallery"),
+            (ItakuPostsExtractor    , base + "posts"),
+            (ItakuFollowersExtractor, base + "followers"),
+            (ItakuFollowingExtractor, base + "following"),
+            (ItakuStarsExtractor    , base + "stars"),
         ), ("gallery",))
 
 
 class ItakuImageExtractor(ItakuExtractor):
     subcategory = "image"
-    pattern = rf"{BASE_PATTERN}/images/(\d+)"
+    pattern = BASE_PATTERN + r"/images/(\d+)"
     example = "https://itaku.ee/images/12345"
 
     def images(self):
@@ -205,7 +205,7 @@ class ItakuPostExtractor(ItakuExtractor):
                      "{id}{title:? //}")
     filename_fmt = "{file[id]}{file[title]:? //}.{extension}"
     archive_fmt = "{id}_{file[id]}"
-    pattern = rf"{BASE_PATTERN}/posts/(\d+)"
+    pattern = BASE_PATTERN + r"/posts/(\d+)"
     example = "https://itaku.ee/posts/12345"
 
     def posts(self):
@@ -214,7 +214,7 @@ class ItakuPostExtractor(ItakuExtractor):
 
 class ItakuSearchExtractor(ItakuExtractor):
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/home/images/?\?([^#]+)"
+    pattern = BASE_PATTERN + r"/home/images/?\?([^#]+)"
     example = "https://itaku.ee/home/images?tags=SEARCH"
 
     def images(self):
@@ -246,7 +246,7 @@ class ItakuAPI():
 
     def __init__(self, extractor):
         self.extractor = extractor
-        self.root = f"{extractor.root}/api"
+        self.root = extractor.root + "/api"
         self.headers = {
             "Accept": "application/json, text/plain, */*",
         }
@@ -309,7 +309,7 @@ class ItakuAPI():
 
     def _call(self, endpoint, params=None):
         if not endpoint.startswith("http"):
-            endpoint = f"{self.root}{endpoint}"
+            endpoint = self.root + endpoint
         return self.extractor.request_json(
             endpoint, params=params, headers=self.headers)
 
diff --git a/gallery_dl/extractor/iwara.py b/gallery_dl/extractor/iwara.py
index d9d1cf0a..5a2049d7 100644
--- a/gallery_dl/extractor/iwara.py
+++ b/gallery_dl/extractor/iwara.py
@@ -12,7 +12,7 @@ from ..cache import cache, memcache
 import hashlib
 
 BASE_PATTERN = r"(?:https?://)?(?:www\.)?iwara\.tv"
-USER_PATTERN = rf"{BASE_PATTERN}/profile/([^/?#]+)"
+USER_PATTERN = BASE_PATTERN + r"/profile/([^/?#]+)"
 
 
 class IwaraExtractor(Extractor):
@@ -79,10 +79,10 @@ class IwaraExtractor(Extractor):
                 continue
 
             yield Message.Directory, "", info
-            yield Message.Url, f"https:{download_url}", info
+            yield Message.Url, "https:" + download_url, info
 
     def items_user(self, users, key=None):
-        base = f"{self.root}/profile/"
+        base = self.root + "/profile/"
         for user in users:
             if key is not None:
                 user = user[key]
@@ -90,7 +90,7 @@ class IwaraExtractor(Extractor):
                 continue
             user["type"] = "user"
             user["_extractor"] = IwaraUserExtractor
-            yield Message.Queue, f"{base}{username}", user
+            yield Message.Queue, base + username, user
 
     def items_by_type(self, type, results):
         if type == "image":
@@ -158,21 +158,21 @@ class IwaraExtractor(Extractor):
 
 class IwaraUserExtractor(Dispatch, IwaraExtractor):
     """Extractor for iwara.tv profile pages"""
-    pattern = rf"{USER_PATTERN}/?$"
+    pattern = USER_PATTERN + r"/?$"
     example = "https://www.iwara.tv/profile/USERNAME"
 
     def items(self):
         base = f"{self.root}/profile/{self.groups[0]}/"
         return self._dispatch_extractors((
-            (IwaraUserImagesExtractor   , f"{base}images"),
-            (IwaraUserVideosExtractor   , f"{base}videos"),
-            (IwaraUserPlaylistsExtractor, f"{base}playlists"),
+            (IwaraUserImagesExtractor   , base + "images"),
+            (IwaraUserVideosExtractor   , base + "videos"),
+            (IwaraUserPlaylistsExtractor, base + "playlists"),
         ), ("user-images", "user-videos"))
 
 
 class IwaraUserImagesExtractor(IwaraExtractor):
     subcategory = "user-images"
-    pattern = rf"{USER_PATTERN}/images(?:\?([^#]+))?"
+    pattern = USER_PATTERN + r"/images(?:\?([^#]+))?"
     example = "https://www.iwara.tv/profile/USERNAME/images"
 
     def items(self):
@@ -182,7 +182,7 @@ class IwaraUserImagesExtractor(IwaraExtractor):
 
 class IwaraUserVideosExtractor(IwaraExtractor):
     subcategory = "user-videos"
-    pattern = rf"{USER_PATTERN}/videos(?:\?([^#]+))?"
+    pattern = USER_PATTERN + r"/videos(?:\?([^#]+))?"
     example = "https://www.iwara.tv/profile/USERNAME/videos"
 
     def items(self):
@@ -192,22 +192,22 @@ class IwaraUserVideosExtractor(IwaraExtractor):
 
 class IwaraUserPlaylistsExtractor(IwaraExtractor):
     subcategory = "user-playlists"
-    pattern = rf"{USER_PATTERN}/playlists(?:\?([^#]+))?"
+    pattern = USER_PATTERN + r"/playlists(?:\?([^#]+))?"
     example = "https://www.iwara.tv/profile/USERNAME/playlists"
 
     def items(self):
-        base = f"{self.root}/playlist/"
+        base = self.root + "/playlist/"
 
         for playlist in self.api.playlists(self._user_params()[1]):
             playlist["type"] = "playlist"
             playlist["_extractor"] = IwaraPlaylistExtractor
-            url = f"{base}{playlist['id']}"
+            url = base + playlist["id"]
             yield Message.Queue, url, playlist
 
 
 class IwaraFollowingExtractor(IwaraExtractor):
     subcategory = "following"
-    pattern = rf"{USER_PATTERN}/following"
+    pattern = USER_PATTERN + r"/following"
     example = "https://www.iwara.tv/profile/USERNAME/following"
 
     def items(self):
@@ -217,7 +217,7 @@ class IwaraFollowingExtractor(IwaraExtractor):
 
 class IwaraFollowersExtractor(IwaraExtractor):
     subcategory = "followers"
-    pattern = rf"{USER_PATTERN}/followers"
+    pattern = USER_PATTERN + r"/followers"
     example = "https://www.iwara.tv/profile/USERNAME/followers"
 
     def items(self):
@@ -228,7 +228,7 @@ class IwaraFollowersExtractor(IwaraExtractor):
 class IwaraImageExtractor(IwaraExtractor):
     """Extractor for individual iwara.tv image pages"""
     subcategory = "image"
-    pattern = rf"{BASE_PATTERN}/image/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/image/([^/?#]+)"
     example = "https://www.iwara.tv/image/ID"
 
     def items(self):
@@ -238,7 +238,7 @@ class IwaraImageExtractor(IwaraExtractor):
 class IwaraVideoExtractor(IwaraExtractor):
     """Extractor for individual iwara.tv videos"""
     subcategory = "video"
-    pattern = rf"{BASE_PATTERN}/video/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/video/([^/?#]+)"
     example = "https://www.iwara.tv/video/ID"
 
     def items(self):
@@ -248,7 +248,7 @@ class IwaraVideoExtractor(IwaraExtractor):
 class IwaraPlaylistExtractor(IwaraExtractor):
     """Extractor for individual iwara.tv playlist pages"""
     subcategory = "playlist"
-    pattern = rf"{BASE_PATTERN}/playlist/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/playlist/([^/?#]+)"
     example = "https://www.iwara.tv/playlist/ID"
 
     def items(self):
@@ -257,7 +257,7 @@ class IwaraPlaylistExtractor(IwaraExtractor):
 
 class IwaraFavoriteExtractor(IwaraExtractor):
     subcategory = "favorite"
-    pattern = rf"{BASE_PATTERN}/favorites(?:/(image|video)s)?"
+    pattern = BASE_PATTERN + r"/favorites(?:/(image|video)s)?"
     example = "https://www.iwara.tv/favorites/videos"
 
     def items(self):
@@ -268,7 +268,7 @@ class IwaraFavoriteExtractor(IwaraExtractor):
 class IwaraSearchExtractor(IwaraExtractor):
     """Extractor for iwara.tv search pages"""
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/search\?([^#]+)"
+    pattern = BASE_PATTERN + r"/search\?([^#]+)"
     example = "https://www.iwara.tv/search?query=QUERY&type=TYPE"
 
     def items(self):
@@ -281,7 +281,7 @@ class IwaraSearchExtractor(IwaraExtractor):
 class IwaraTagExtractor(IwaraExtractor):
     """Extractor for iwara.tv tag search"""
     subcategory = "tag"
-    pattern = rf"{BASE_PATTERN}/(image|video)s(?:\?([^#]+))?"
+    pattern = BASE_PATTERN + r"/(image|video)s(?:\?([^#]+))?"
     example = "https://www.iwara.tv/videos?tags=TAGS"
 
     def items(self):
@@ -298,7 +298,7 @@ class IwaraAPI():
     def __init__(self, extractor):
         self.extractor = extractor
         self.headers = {
-            "Referer"     : f"{extractor.root}/",
+            "Referer"     : extractor.root + "/",
             "Content-Type": "application/json",
             "Origin"      : extractor.root,
         }
@@ -308,15 +308,15 @@ class IwaraAPI():
             self.authenticate = util.noop
 
     def image(self, image_id):
-        endpoint = f"/image/{image_id}"
+        endpoint = "/image/" + image_id
         return self._call(endpoint)
 
     def video(self, video_id):
-        endpoint = f"/video/{video_id}"
+        endpoint = "/video/" + video_id
         return self._call(endpoint)
 
     def playlist(self, playlist_id):
-        endpoint = f"/playlist/{playlist_id}"
+        endpoint = "/playlist/" + playlist_id
         return self._pagination(endpoint)
 
     def detail(self, media):
@@ -356,7 +356,7 @@ class IwaraAPI():
 
     @memcache(keyarg=1)
     def profile(self, username):
-        endpoint = f"/profile/{username}"
+        endpoint = "/profile/" + username
         return self._call(endpoint)
 
     def user_following(self, user_id):
@@ -387,7 +387,7 @@ class IwaraAPI():
         if refresh_token is None:
             self.extractor.log.info("Logging in as %s", username)
 
-            url = f"{self.root}/user/login"
+            url = self.root + "/user/login"
             json = {
                 "email"   : username,
                 "password": self.password
@@ -403,15 +403,15 @@ class IwaraAPI():
 
         self.extractor.log.info("Refreshing access token for %s", username)
 
-        url = f"{self.root}/user/token"
-        headers = {"Authorization": f"Bearer {refresh_token}", **self.headers}
+        url = self.root + "/user/token"
+        headers = {"Authorization": "Bearer " + refresh_token, **self.headers}
         data = self.extractor.request_json(
             url, method="POST", headers=headers, fatal=False)
 
         if not (access_token := data.get("accessToken")):
             self.extractor.log.debug(data)
             raise exception.AuthenticationError(data.get("message"))
-        return f"Bearer {access_token}"
+        return "Bearer " + access_token
 
     def _call(self, endpoint, params=None, headers=None):
         if headers is None:
diff --git a/gallery_dl/extractor/jschan.py b/gallery_dl/extractor/jschan.py
index 5dacf70b..6e03e7b9 100644
--- a/gallery_dl/extractor/jschan.py
+++ b/gallery_dl/extractor/jschan.py
@@ -30,7 +30,7 @@ class JschanThreadExtractor(JschanExtractor):
                      "{threadId} {subject|nomarkup[:50]}")
     filename_fmt = "{postId}{num:?-//} {filename}.{extension}"
     archive_fmt = "{board}_{postId}_{num}"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/thread/(\d+)\.html"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/thread/(\d+)\.html"
     example = "https://94chan.org/a/thread/12345.html"
 
     def items(self):
@@ -56,7 +56,7 @@ class JschanThreadExtractor(JschanExtractor):
 class JschanBoardExtractor(JschanExtractor):
     """Extractor for jschan boards"""
     subcategory = "board"
-    pattern = (rf"{BASE_PATTERN}/([^/?#]+)"
+    pattern = (BASE_PATTERN + r"/([^/?#]+)"
                r"(?:/index\.html|/catalog\.html|/\d+\.html|/?$)")
     example = "https://94chan.org/a/"
 
diff --git a/gallery_dl/extractor/kabeuchi.py b/gallery_dl/extractor/kabeuchi.py
index 88f2e327..e41e9b0e 100644
--- a/gallery_dl/extractor/kabeuchi.py
+++ b/gallery_dl/extractor/kabeuchi.py
@@ -52,7 +52,7 @@ class KabeuchiUserExtractor(Extractor):
         return self._pagination(target_id)
 
     def _pagination(self, target_id):
-        url = f"{self.root}/get_posts.php"
+        url = self.root + "/get_posts.php"
         data = {
             "user_id"    : "0",
             "target_id"  : target_id,
diff --git a/gallery_dl/extractor/kemono.py b/gallery_dl/extractor/kemono.py
index bf35670e..a001d106 100644
--- a/gallery_dl/extractor/kemono.py
+++ b/gallery_dl/extractor/kemono.py
@@ -16,7 +16,7 @@ import json
 
 BASE_PATTERN = (r"(?:https?://)?(?:www\.|beta\.)?"
                 r"(kemono|coomer)\.(cr|s[tu]|party)")
-USER_PATTERN = rf"{BASE_PATTERN}/([^/?#]+)/user/([^/?#]+)"
+USER_PATTERN = BASE_PATTERN + r"/([^/?#]+)/user/([^/?#]+)"
 HASH_PATTERN = r"/[0-9a-f]{2}/[0-9a-f]{2}/([0-9a-f]{64})"
 
 
@@ -200,7 +200,7 @@ class KemonoExtractor(Extractor):
         username = username[0]
         self.log.info("Logging in as %s", username)
 
-        url = f"{self.root}/api/v1/authentication/login"
+        url = self.root + "/api/v1/authentication/login"
         data = {"username": username, "password": password}
 
         response = self.request(url, method="POST", json=data, fatal=False)
@@ -322,7 +322,7 @@ def _validate(response):
 class KemonoUserExtractor(KemonoExtractor):
     """Extractor for all posts from a kemono.cr user listing"""
     subcategory = "user"
-    pattern = rf"{USER_PATTERN}/?(?:\?([^#]+))?(?:$|\?|#)"
+    pattern = USER_PATTERN + r"/?(?:\?([^#]+))?(?:$|\?|#)"
     example = "https://kemono.cr/SERVICE/user/12345"
 
     def __init__(self, match):
@@ -345,7 +345,7 @@ class KemonoUserExtractor(KemonoExtractor):
 class KemonoPostsExtractor(KemonoExtractor):
     """Extractor for kemono.cr post listings"""
     subcategory = "posts"
-    pattern = rf"{BASE_PATTERN}/posts()()(?:/?\?([^#]+))?"
+    pattern = BASE_PATTERN + r"/posts()()(?:/?\?([^#]+))?"
     example = "https://kemono.cr/posts"
 
     def posts(self):
@@ -357,7 +357,7 @@ class KemonoPostsExtractor(KemonoExtractor):
 class KemonoPostExtractor(KemonoExtractor):
     """Extractor for a single kemono.cr post"""
     subcategory = "post"
-    pattern = rf"{USER_PATTERN}/post/([^/?#]+)(/revisions?(?:/(\d*))?)?"
+    pattern = USER_PATTERN + r"/post/([^/?#]+)(/revisions?(?:/(\d*))?)?"
     example = "https://kemono.cr/SERVICE/user/12345/post/12345"
 
     def __init__(self, match):
@@ -390,7 +390,7 @@ class KemonoDiscordExtractor(KemonoExtractor):
                      "{server_id} {server}", "{channel_id} {channel}")
     filename_fmt = "{id}_{num:>02}_{filename}.{extension}"
     archive_fmt = "discord_{server_id}_{id}_{num}"
-    pattern = rf"{BASE_PATTERN}/discord/server/(\d+)[/#](?:channel/)?(\d+)"
+    pattern = BASE_PATTERN + r"/discord/server/(\d+)[/#](?:channel/)?(\d+)"
     example = "https://kemono.cr/discord/server/12345/12345"
 
     def items(self):
@@ -434,7 +434,7 @@ class KemonoDiscordExtractor(KemonoExtractor):
                 attachment["type"] = "attachment"
                 files.append(attachment)
             for path in find_inline(post["content"] or ""):
-                files.append({"path": f"https://cdn.discordapp.com{path}",
+                files.append({"path": "https://cdn.discordapp.com" + path,
                               "name": path, "type": "inline", "hash": ""})
 
             post.update(data)
@@ -460,7 +460,7 @@ class KemonoDiscordExtractor(KemonoExtractor):
 
 class KemonoDiscordServerExtractor(KemonoExtractor):
     subcategory = "discord-server"
-    pattern = rf"{BASE_PATTERN}/discord/server/(\d+)$"
+    pattern = BASE_PATTERN + r"/discord/server/(\d+)$"
     example = "https://kemono.cr/discord/server/12345"
 
     def items(self):
@@ -488,7 +488,7 @@ def discord_server_info(extr, server_id):
 class KemonoFavoriteExtractor(KemonoExtractor):
     """Extractor for kemono.cr favorites"""
     subcategory = "favorite"
-    pattern = rf"{BASE_PATTERN}/(?:account/)?favorites()()(?:/?\?([^#]+))?"
+    pattern = BASE_PATTERN + r"/(?:account/)?favorites()()(?:/?\?([^#]+))?"
     example = "https://kemono.cr/account/favorites/artists"
 
     def items(self):
@@ -536,7 +536,7 @@ class KemonoFavoriteExtractor(KemonoExtractor):
 class KemonoArtistsExtractor(KemonoExtractor):
     """Extractor for kemono artists"""
     subcategory = "artists"
-    pattern = rf"{BASE_PATTERN}/artists(?:\?([^#]+))?"
+    pattern = BASE_PATTERN + r"/artists(?:\?([^#]+))?"
     example = "https://kemono.cr/artists"
 
     def items(self):
@@ -577,7 +577,7 @@ class KemonoAPI():
 
     def __init__(self, extractor):
         self.extractor = extractor
-        self.root = f"{extractor.root}/api"
+        self.root = extractor.root + "/api"
         self.headers = {"Accept": "text/css"}
 
     def posts(self, offset=0, query=None, tags=None):
@@ -586,7 +586,7 @@ class KemonoAPI():
         return self._pagination(endpoint, params, 50, "posts")
 
     def file(self, file_hash):
-        endpoint = f"/v1/file/{file_hash}"
+        endpoint = "/v1/file/" + file_hash
         return self._call(endpoint)
 
     def creators(self):
@@ -643,18 +643,18 @@ class KemonoAPI():
         return self._call(endpoint)
 
     def discord_channel(self, channel_id, post_count=None):
-        endpoint = f"/v1/discord/channel/{channel_id}"
+        endpoint = "/v1/discord/channel/" + channel_id
         if post_count is None:
             return self._pagination(endpoint, {}, 150)
         else:
             return self._pagination_reverse(endpoint, {}, 150, post_count)
 
     def discord_channel_lookup(self, server_id):
-        endpoint = f"/v1/discord/channel/lookup/{server_id}"
+        endpoint = "/v1/discord/channel/lookup/" + server_id
         return self._call(endpoint)
 
     def discord_server(self, server_id):
-        endpoint = f"/v1/discord/server/{server_id}"
+        endpoint = "/v1/discord/server/" + server_id
         return self._call(endpoint)
 
     def account_favorites(self, type):
@@ -669,7 +669,7 @@ class KemonoAPI():
             headers = {**self.headers, **headers}
 
         return self.extractor.request_json(
-            f"{self.root}{endpoint}", params=params, headers=headers,
+            self.root + endpoint, params=params, headers=headers,
             encoding="utf-8", fatal=fatal)
 
     def _pagination(self, endpoint, params, batch=50, key=None):
diff --git a/gallery_dl/extractor/komikcast.py b/gallery_dl/extractor/komikcast.py
index e2f00e1c..fad63c94 100644
--- a/gallery_dl/extractor/komikcast.py
+++ b/gallery_dl/extractor/komikcast.py
@@ -44,7 +44,7 @@ class KomikcastBase():
 
 class KomikcastChapterExtractor(KomikcastBase, ChapterExtractor):
     """Extractor for komikcast manga chapters"""
-    pattern = rf"{BASE_PATTERN}(/chapter/[^/?#]+/)"
+    pattern = BASE_PATTERN + r"(/chapter/[^/?#]+/)"
     example = "https://komikcast.li/chapter/TITLE/"
 
     def metadata(self, page):
@@ -64,7 +64,7 @@ class KomikcastChapterExtractor(KomikcastBase, ChapterExtractor):
 class KomikcastMangaExtractor(KomikcastBase, MangaExtractor):
     """Extractor for komikcast manga"""
     chapterclass = KomikcastChapterExtractor
-    pattern = rf"{BASE_PATTERN}(/(?:komik/)?[^/?#]+/?)$"
+    pattern = BASE_PATTERN + r"(/(?:komik/)?[^/?#]+/?)$"
     example = "https://komikcast.li/komik/TITLE"
 
     def chapters(self, page):
diff --git a/gallery_dl/extractor/leakgallery.py b/gallery_dl/extractor/leakgallery.py
index 2939304c..d119ac6b 100644
--- a/gallery_dl/extractor/leakgallery.py
+++ b/gallery_dl/extractor/leakgallery.py
@@ -35,7 +35,7 @@ class LeakgalleryExtractor(Extractor):
             else:
                 media["creator"] = creator
 
-            media["url"] = url = f"https://cdn.leakgallery.com/{path}"
+            media["url"] = url = "https://cdn.leakgallery.com/" + path
             text.nameext_from_url(url, media)
             yield Message.Directory, "", media
             yield Message.Url, url, media
@@ -43,7 +43,7 @@ class LeakgalleryExtractor(Extractor):
     def _pagination(self, type, base, params=None, creator=None, pnum=1):
         while True:
             try:
-                data = self.request_json(f"{base}{pnum}", params=params)
+                data = self.request_json(base + str(pnum), params=params)
 
                 if not data:
                     return
@@ -81,7 +81,7 @@ class LeakgalleryUserExtractor(LeakgalleryExtractor):
 class LeakgalleryTrendingExtractor(LeakgalleryExtractor):
     """Extractor for trending posts on leakgallery.com"""
     subcategory = "trending"
-    pattern = rf"{BASE_PATTERN}/trending-medias(?:/([\w-]+))?"
+    pattern = BASE_PATTERN + r"/trending-medias(?:/([\w-]+))?"
     example = "https://leakgallery.com/trending-medias/Week"
 
     def items(self):
@@ -93,7 +93,7 @@ class LeakgalleryTrendingExtractor(LeakgalleryExtractor):
 class LeakgalleryMostlikedExtractor(LeakgalleryExtractor):
     """Extractor for most liked posts on leakgallery.com"""
     subcategory = "mostliked"
-    pattern = rf"{BASE_PATTERN}/most-liked"
+    pattern = BASE_PATTERN + r"/most-liked"
     example = "https://leakgallery.com/most-liked"
 
     def items(self):
@@ -104,7 +104,7 @@ class LeakgalleryMostlikedExtractor(LeakgalleryExtractor):
 class LeakgalleryPostExtractor(LeakgalleryExtractor):
     """Extractor for individual posts on leakgallery.com"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/(\d+)"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/(\d+)"
     example = "https://leakgallery.com/CREATOR/12345"
 
     def items(self):
diff --git a/gallery_dl/extractor/lensdump.py b/gallery_dl/extractor/lensdump.py
index a7b13187..124991a2 100644
--- a/gallery_dl/extractor/lensdump.py
+++ b/gallery_dl/extractor/lensdump.py
@@ -31,7 +31,7 @@ class LensdumpBase():
 
 class LensdumpAlbumExtractor(LensdumpBase, GalleryExtractor):
     subcategory = "album"
-    pattern = rf"{BASE_PATTERN}/a/(\w+)(?:/?\?([^#]+))?"
+    pattern = BASE_PATTERN + r"/a/(\w+)(?:/?\?([^#]+))?"
     example = "https://lensdump.com/a/ID"
 
     def __init__(self, match):
@@ -76,7 +76,7 @@ class LensdumpAlbumExtractor(LensdumpBase, GalleryExtractor):
 class LensdumpAlbumsExtractor(LensdumpBase, Extractor):
     """Extractor for album list from lensdump.com"""
     subcategory = "albums"
-    pattern = rf"{BASE_PATTERN}/(?![ai]/)([^/?#]+)(?:/?\?([^#]+))?"
+    pattern = BASE_PATTERN + r"/(?![ai]/)([^/?#]+)(?:/?\?([^#]+))?"
     example = "https://lensdump.com/USER"
 
     def items(self):
diff --git a/gallery_dl/extractor/lolisafe.py b/gallery_dl/extractor/lolisafe.py
index d17549de..1ddce55b 100644
--- a/gallery_dl/extractor/lolisafe.py
+++ b/gallery_dl/extractor/lolisafe.py
@@ -25,7 +25,7 @@ BASE_PATTERN = LolisafeExtractor.update({
 
 class LolisafeAlbumExtractor(LolisafeExtractor):
     subcategory = "album"
-    pattern = rf"{BASE_PATTERN}/a/([^/?#]+)"
+    pattern = BASE_PATTERN + "/a/([^/?#]+)"
     example = "https://xbunkr.com/a/ID"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/lynxchan.py b/gallery_dl/extractor/lynxchan.py
index 7cf12828..86b317a3 100644
--- a/gallery_dl/extractor/lynxchan.py
+++ b/gallery_dl/extractor/lynxchan.py
@@ -39,7 +39,7 @@ class LynxchanThreadExtractor(LynxchanExtractor):
                      "{threadId} {subject|message[:50]}")
     filename_fmt = "{postId}{num:?-//} {filename}.{extension}"
     archive_fmt = "{boardUri}_{postId}_{num}"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/res/(\d+)"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/res/(\d+)"
     example = "https://endchan.org/a/res/12345.html"
 
     def items(self):
@@ -63,7 +63,7 @@ class LynxchanThreadExtractor(LynxchanExtractor):
 class LynxchanBoardExtractor(LynxchanExtractor):
     """Extractor for LynxChan boards"""
     subcategory = "board"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)(?:/index|/catalog|/\d+|/?$)"
+    pattern = BASE_PATTERN + r"/([^/?#]+)(?:/index|/catalog|/\d+|/?$)"
     example = "https://endchan.org/a/"
 
     def items(self):
diff --git a/gallery_dl/extractor/madokami.py b/gallery_dl/extractor/madokami.py
index e15b90d7..0b90e8ef 100644
--- a/gallery_dl/extractor/madokami.py
+++ b/gallery_dl/extractor/madokami.py
@@ -25,7 +25,7 @@ class MadokamiMangaExtractor(MadokamiExtractor):
     subcategory = "manga"
     directory_fmt = ("{category}", "{manga}")
     archive_fmt = "{chapter_id}"
-    pattern = rf"{BASE_PATTERN}/Manga/(\w/\w{{2}}/\w{{4}}/.+)"
+    pattern = BASE_PATTERN + r"/Manga/(\w/\w{2}/\w{4}/.+)"
     example = "https://manga.madokami.al/Manga/A/AB/ABCD/ABCDE_TITLE"
 
     def items(self):
@@ -85,7 +85,7 @@ class MadokamiMangaExtractor(MadokamiExtractor):
             else:
                 ch["volume"] = ch["chapter"] = ch["chapter_end"] = 0
 
-            url = f"{self.root}{ch['path']}"
+            url = self.root + ch["path"]
             text.nameext_from_url(url, ch)
 
             yield Message.Directory, "", ch
diff --git a/gallery_dl/extractor/mangadex.py b/gallery_dl/extractor/mangadex.py
index 0a1709d7..12e5f8d5 100644
--- a/gallery_dl/extractor/mangadex.py
+++ b/gallery_dl/extractor/mangadex.py
@@ -66,7 +66,7 @@ class MangadexExtractor(Extractor):
             "title"   : cattributes["title"],
             "volume"  : text.parse_int(cattributes["volume"]),
             "chapter" : text.parse_int(chnum),
-            "chapter_minor": f"{sep}{minor}",
+            "chapter_minor": sep + minor,
             "chapter_id": chapter["id"],
             "date"    : self.parse_datetime_iso(cattributes["publishAt"]),
             "group"   : [group["attributes"]["name"]
@@ -83,8 +83,8 @@ class MangadexCoversExtractor(MangadexExtractor):
     directory_fmt = ("{category}", "{manga}", "Covers")
     filename_fmt = "{volume:>02}_{lang}.{extension}"
     archive_fmt = "c_{cover_id}"
-    pattern = (rf"{BASE_PATTERN}/(?:title|manga)/(?!follows|feed$)([0-9a-f-]+)"
-               rf"(?:/[^/?#]+)?\?tab=art")
+    pattern = (BASE_PATTERN + r"/(?:title|manga)/(?!follows|feed$)([0-9a-f-]+)"
+               r"(?:/[^/?#]+)?\?tab=art")
     example = ("https://mangadex.org/title"
                "/01234567-89ab-cdef-0123-456789abcdef?tab=art")
 
@@ -96,7 +96,7 @@ class MangadexCoversExtractor(MangadexExtractor):
             text.nameext_from_url(name, data)
             data["cover_id"] = data["filename"]
             yield Message.Directory, "", data
-            yield Message.Url, f"{base}{name}", data
+            yield Message.Url, base + name, data
 
     def _transform_cover(self, cover):
         relationships = defaultdict(list)
@@ -117,7 +117,7 @@ class MangadexCoversExtractor(MangadexExtractor):
 class MangadexChapterExtractor(MangadexExtractor):
     """Extractor for manga-chapters from mangadex.org"""
     subcategory = "chapter"
-    pattern = rf"{BASE_PATTERN}/chapter/([0-9a-f-]+)"
+    pattern = BASE_PATTERN + r"/chapter/([0-9a-f-]+)"
     example = ("https://mangadex.org/chapter"
                "/01234567-89ab-cdef-0123-456789abcdef")
 
@@ -148,15 +148,15 @@ class MangadexChapterExtractor(MangadexExtractor):
 
         enum = util.enumerate_reversed if self.config(
             "page-reverse") else enumerate
-        for data["page"], page in enum(chapter[key], 1):
-            text.nameext_from_url(page, data)
-            yield Message.Url, f"{base}{page}", data
+        for data["page"], path in enum(chapter[key], 1):
+            text.nameext_from_url(path, data)
+            yield Message.Url, base + path, data
 
 
 class MangadexMangaExtractor(MangadexExtractor):
     """Extractor for manga from mangadex.org"""
     subcategory = "manga"
-    pattern = rf"{BASE_PATTERN}/(?:title|manga)/(?!follows|feed$)([0-9a-f-]+)"
+    pattern = BASE_PATTERN + r"/(?:title|manga)/(?!follows|feed$)([0-9a-f-]+)"
     example = ("https://mangadex.org/title"
                "/01234567-89ab-cdef-0123-456789abcdef")
 
@@ -167,7 +167,7 @@ class MangadexMangaExtractor(MangadexExtractor):
 class MangadexFeedExtractor(MangadexExtractor):
     """Extractor for chapters from your Updates Feed"""
     subcategory = "feed"
-    pattern = rf"{BASE_PATTERN}/titles?/feed$()"
+    pattern = BASE_PATTERN + r"/titles?/feed$()"
     example = "https://mangadex.org/title/feed"
 
     def chapters(self):
@@ -177,7 +177,7 @@ class MangadexFeedExtractor(MangadexExtractor):
 class MangadexFollowingExtractor(MangadexExtractor):
     """Extractor for followed manga from your Library"""
     subcategory = "following"
-    pattern = rf"{BASE_PATTERN}/titles?/follows(?:\?([^#]+))?$"
+    pattern = BASE_PATTERN + r"/titles?/follows(?:\?([^#]+))?$"
     example = "https://mangadex.org/title/follows"
 
     items = MangadexExtractor._items_manga
@@ -189,8 +189,8 @@ class MangadexFollowingExtractor(MangadexExtractor):
 class MangadexListExtractor(MangadexExtractor):
     """Extractor for mangadex MDLists"""
     subcategory = "list"
-    pattern = (rf"{BASE_PATTERN}"
-               rf"/list/([0-9a-f-]+)(?:/[^/?#]*)?(?:\?tab=(\w+))?")
+    pattern = (BASE_PATTERN +
+               r"/list/([0-9a-f-]+)(?:/[^/?#]*)?(?:\?tab=(\w+))?")
     example = ("https://mangadex.org/list"
                "/01234567-89ab-cdef-0123-456789abcdef/NAME")
 
@@ -215,7 +215,7 @@ class MangadexListExtractor(MangadexExtractor):
 class MangadexAuthorExtractor(MangadexExtractor):
     """Extractor for mangadex authors"""
     subcategory = "author"
-    pattern = rf"{BASE_PATTERN}/author/([0-9a-f-]+)"
+    pattern = BASE_PATTERN + r"/author/([0-9a-f-]+)"
     example = ("https://mangadex.org/author"
                "/01234567-89ab-cdef-0123-456789abcdef/NAME")
 
@@ -253,22 +253,22 @@ class MangadexAPI():
                      else text.ensure_http_scheme(server).rstrip("/"))
 
     def athome_server(self, uuid):
-        return self._call(f"/at-home/server/{uuid}")
+        return self._call("/at-home/server/" + uuid)
 
     def author(self, uuid, manga=False):
         params = {"includes[]": ("manga",)} if manga else None
-        return self._call(f"/author/{uuid}", params)["data"]
+        return self._call("/author/" + uuid, params)["data"]
 
     def chapter(self, uuid):
         params = {"includes[]": ("scanlation_group",)}
-        return self._call(f"/chapter/{uuid}", params)["data"]
+        return self._call("/chapter/" + uuid, params)["data"]
 
     def covers_manga(self, uuid):
         params = {"manga[]": uuid}
         return self._pagination_covers("/cover", params)
 
     def list(self, uuid):
-        return self._call(f"/list/{uuid}", None, True)["data"]
+        return self._call("/list/" + uuid, None, True)["data"]
 
     def list_feed(self, uuid):
         return self._pagination_chapters(f"/list/{uuid}/feed", None, True)
@@ -276,7 +276,7 @@ class MangadexAPI():
     @memcache(keyarg=1)
     def manga(self, uuid):
         params = {"includes[]": ("artist", "author")}
-        return self._call(f"/manga/{uuid}", params)["data"]
+        return self._call("/manga/" + uuid, params)["data"]
 
     def manga_author(self, uuid_author):
         params = {"authorOrArtist": uuid_author}
@@ -339,17 +339,17 @@ class MangadexAPI():
             _refresh_token_cache.update(
                 (username, "personal"), data["refresh_token"])
 
-        return f"Bearer {access_token}"
+        return "Bearer " + access_token
 
     @cache(maxage=900, keyarg=1)
     def _authenticate_impl_legacy(self, username, password):
         if refresh_token := _refresh_token_cache(username):
             self.extractor.log.info("Refreshing access token")
-            url = f"{self.root}/auth/refresh"
+            url = self.root + "/auth/refresh"
             json = {"token": refresh_token}
         else:
             self.extractor.log.info("Logging in as %s", username)
-            url = f"{self.root}/auth/login"
+            url = self.root + "/auth/login"
             json = {"username": username, "password": password}
 
         self.extractor.log.debug("Using legacy login method")
@@ -360,10 +360,10 @@ class MangadexAPI():
 
         if refresh_token != data["token"]["refresh"]:
             _refresh_token_cache.update(username, data["token"]["refresh"])
-        return f"Bearer {data['token']['session']}"
+        return "Bearer " + data["token"]["session"]
 
     def _call(self, endpoint, params=None, auth=False):
-        url = f"{self.root}{endpoint}"
+        url = self.root + endpoint
         headers = self.headers_auth if auth else self.headers
 
         while True:
diff --git a/gallery_dl/extractor/mangafire.py b/gallery_dl/extractor/mangafire.py
index 5ccb7323..8db91b32 100644
--- a/gallery_dl/extractor/mangafire.py
+++ b/gallery_dl/extractor/mangafire.py
@@ -31,8 +31,8 @@ class MangafireChapterExtractor(MangafireBase, ChapterExtractor):
         "{page:>03}.{extension}")
     archive_fmt = (
         "{manga_id}_{chapter_id}_{page}")
-    pattern = (rf"{BASE_PATTERN}/read/([\w-]+\.(\w+))/([\w-]+)"
-               rf"/((chapter|volume)-\d+(?:\D.*)?)")
+    pattern = (BASE_PATTERN + r"/read/([\w-]+\.(\w+))/([\w-]+)"
+               r"/((chapter|volume)-\d+(?:\D.*)?)")
     example = "https://mangafire.to/read/MANGA.ID/LANG/chapter-123"
 
     def metadata(self, _):
@@ -64,7 +64,7 @@ class MangafireChapterExtractor(MangafireBase, ChapterExtractor):
 class MangafireMangaExtractor(MangafireBase, MangaExtractor):
     """Extractor for mangafire manga"""
     chapterclass = MangafireChapterExtractor
-    pattern = rf"{BASE_PATTERN}/manga/([\w-]+)\.(\w+)"
+    pattern = BASE_PATTERN + r"/manga/([\w-]+)\.(\w+)"
     example = "https://mangafire.to/manga/MANGA.ID"
 
     def chapters(self, page):
@@ -75,7 +75,7 @@ class MangafireMangaExtractor(MangafireBase, MangaExtractor):
         chapters = _manga_chapters(self, (manga_id, "chapter", lang))
 
         return [
-            (f"""{self.root}{text.extr(anchor, 'href="', '"')}""", {
+            (self.root + text.extr(anchor, 'href="', '"'), {
                 **manga,
                 **_chapter_info(anchor),
             })
@@ -160,7 +160,7 @@ def _chapter_info(info):
     chapter, sep, minor = text.extr(info, 'data-number="', '"').partition(".")
     return {
         "chapter"       : text.parse_int(chapter),
-        "chapter_minor" : f"{sep}{minor}",
+        "chapter_minor" : sep + minor,
         "chapter_string": chapter_info,
         "chapter_id"    : text.parse_int(text.extr(info, 'data-id="', '"')),
         "title"         : text.unescape(text.extr(info, 'title="', '"')),
diff --git a/gallery_dl/extractor/mangafox.py b/gallery_dl/extractor/mangafox.py
index 8fa645bb..a5f31e3b 100644
--- a/gallery_dl/extractor/mangafox.py
+++ b/gallery_dl/extractor/mangafox.py
@@ -18,8 +18,8 @@ class MangafoxChapterExtractor(ChapterExtractor):
     """Extractor for manga chapters from fanfox.net"""
     category = "mangafox"
     root = "https://m.fanfox.net"
-    pattern = (rf"{BASE_PATTERN}"
-               rf"(/manga/[^/?#]+/((?:v([^/?#]+)/)?c(\d+)([^/?#]*)))")
+    pattern = BASE_PATTERN + \
+        r"(/manga/[^/?#]+/((?:v([^/?#]+)/)?c(\d+)([^/?#]*)))"
     example = "https://fanfox.net/manga/TITLE/v01/c001/1.html"
 
     def __init__(self, match):
@@ -62,7 +62,7 @@ class MangafoxMangaExtractor(MangaExtractor):
     category = "mangafox"
     root = "https://m.fanfox.net"
     chapterclass = MangafoxChapterExtractor
-    pattern = rf"{BASE_PATTERN}(/manga/[^/?#]+)/?$"
+    pattern = BASE_PATTERN + r"(/manga/[^/?#]+)/?$"
     example = "https://fanfox.net/manga/TITLE"
 
     def chapters(self, page):
diff --git a/gallery_dl/extractor/mangahere.py b/gallery_dl/extractor/mangahere.py
index 9b3a3a14..f0cc9280 100644
--- a/gallery_dl/extractor/mangahere.py
+++ b/gallery_dl/extractor/mangahere.py
@@ -28,7 +28,7 @@ class MangahereChapterExtractor(MangahereBase, ChapterExtractor):
     def __init__(self, match):
         self.part, self.volume, self.chapter = match.groups()
         self.base = f"{self.root_mobile}/manga/{self.part}/"
-        ChapterExtractor.__init__(self, match, f"{self.base}1.html")
+        ChapterExtractor.__init__(self, match, self.base + "1.html")
 
     def _init(self):
         self.session.headers["Referer"] = self.root_mobile + "/"
diff --git a/gallery_dl/extractor/manganelo.py b/gallery_dl/extractor/manganelo.py
index 3ecf934d..3d88b2d0 100644
--- a/gallery_dl/extractor/manganelo.py
+++ b/gallery_dl/extractor/manganelo.py
@@ -39,7 +39,7 @@ BASE_PATTERN = ManganeloExtractor.update({
 
 class ManganeloChapterExtractor(ManganeloExtractor, ChapterExtractor):
     """Extractor for manganelo manga chapters"""
-    pattern = rf"{BASE_PATTERN}(/manga/[^/?#]+/chapter-[^/?#]+)"
+    pattern = BASE_PATTERN + r"(/manga/[^/?#]+/chapter-[^/?#]+)"
     example = "https://www.mangakakalot.gg/manga/MANGA_NAME/chapter-123"
 
     def __init__(self, match):
@@ -86,7 +86,7 @@ class ManganeloChapterExtractor(ManganeloExtractor, ChapterExtractor):
 class ManganeloMangaExtractor(ManganeloExtractor, MangaExtractor):
     """Extractor for manganelo manga"""
     chapterclass = ManganeloChapterExtractor
-    pattern = rf"{BASE_PATTERN}(/manga/[^/?#]+)$"
+    pattern = BASE_PATTERN + r"(/manga/[^/?#]+)$"
     example = "https://www.mangakakalot.gg/manga/MANGA_NAME"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/mangapark.py b/gallery_dl/extractor/mangapark.py
index e2f9166b..35fbf190 100644
--- a/gallery_dl/extractor/mangapark.py
+++ b/gallery_dl/extractor/mangapark.py
@@ -70,8 +70,8 @@ class MangaparkBase():
 
 class MangaparkChapterExtractor(MangaparkBase, ChapterExtractor):
     """Extractor for manga-chapters from mangapark.net"""
-    pattern = (rf"{BASE_PATTERN}/"
-               rf"(?:title/[^/?#]+/|comic/\d+/[^/?#]+/[^/?#]+-i)(\d+)")
+    pattern = (BASE_PATTERN +
+               r"/(?:title/[^/?#]+/|comic/\d+/[^/?#]+/[^/?#]+-i)(\d+)")
     example = "https://mangapark.net/title/MANGA/12345-en-ch.01"
 
     def __init__(self, match):
@@ -111,7 +111,7 @@ class MangaparkChapterExtractor(MangaparkBase, ChapterExtractor):
 class MangaparkMangaExtractor(MangaparkBase, Extractor):
     """Extractor for manga from mangapark.net"""
     subcategory = "manga"
-    pattern = rf"{BASE_PATTERN}/(?:title|comic)/(\d+)(?:[/-][^/?#]*)?/?$"
+    pattern = BASE_PATTERN + r"/(?:title|comic)/(\d+)(?:[/-][^/?#]*)?/?$"
     example = "https://mangapark.net/title/12345-MANGA"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/mangareader.py b/gallery_dl/extractor/mangareader.py
index eb53998e..c786c994 100644
--- a/gallery_dl/extractor/mangareader.py
+++ b/gallery_dl/extractor/mangareader.py
@@ -31,8 +31,8 @@ class MangareaderChapterExtractor(MangareaderBase, ChapterExtractor):
         "{page:>03}.{extension}")
     archive_fmt = (
         "{manga_id}_{chapter_id}_{page}")
-    pattern = (rf"{BASE_PATTERN}/read/([\w-]+-\d+)/([^/?#]+)"
-               rf"/(chapter|volume)-(\d+[^/?#]*)")
+    pattern = (BASE_PATTERN + r"/read/([\w-]+-\d+)/([^/?#]+)"
+               r"/(chapter|volume)-(\d+[^/?#]*)")
     example = "https://mangareader.to/read/MANGA-123/LANG/chapter-123"
 
     def metadata(self, _):
@@ -81,7 +81,7 @@ class MangareaderChapterExtractor(MangareaderBase, ChapterExtractor):
 class MangareaderMangaExtractor(MangareaderBase, MangaExtractor):
     """Extractor for mangareader manga"""
     chapterclass = MangareaderChapterExtractor
-    pattern = rf"{BASE_PATTERN}/([\w-]+-\d+)"
+    pattern = BASE_PATTERN + r"/([\w-]+-\d+)"
     example = "https://mangareader.to/MANGA-123"
 
     def chapters(self, page):
@@ -138,9 +138,9 @@ def _manga_info(self, manga_path):
             current[chap] = {
                 "title"         : name.partition(":")[2].strip(),
                 "chapter"       : text.parse_int(chapter),
-                "chapter_minor" : f"{sep}{minor}",
+                "chapter_minor" : sep + minor,
                 "chapter_string": chap,
-                "chapter_url"   : f"{base}{path}",
+                "chapter_url"   : base + path,
                 "lang"          : lang,
             }
 
@@ -162,7 +162,7 @@ def _manga_info(self, manga_path):
                 "chapter"       : 0,
                 "chapter_minor" : "",
                 "chapter_string": voln,
-                "chapter_url"   : f"{base}{path}",
+                "chapter_url"   : base + path,
                 "lang"          : lang,
             }
 
diff --git a/gallery_dl/extractor/mangataro.py b/gallery_dl/extractor/mangataro.py
index 029bc2e9..7d9c1260 100644
--- a/gallery_dl/extractor/mangataro.py
+++ b/gallery_dl/extractor/mangataro.py
@@ -23,7 +23,7 @@ class MangataroBase():
 
 class MangataroChapterExtractor(MangataroBase, ChapterExtractor):
     """Extractor for mangataro manga chapters"""
-    pattern = rf"{BASE_PATTERN}(/read/([^/?#]+)/(?:[^/?#]*-)?(\d+))"
+    pattern = BASE_PATTERN + r"(/read/([^/?#]+)/(?:[^/?#]*-)?(\d+))"
     example = "https://mangataro.org/read/MANGA/ch123-12345"
 
     def metadata(self, page):
@@ -59,7 +59,7 @@ class MangataroChapterExtractor(MangataroBase, ChapterExtractor):
 class MangataroMangaExtractor(MangataroBase, MangaExtractor):
     """Extractor for mangataro manga"""
     chapterclass = MangataroChapterExtractor
-    pattern = rf"{BASE_PATTERN}(/manga/([^/?#]+))"
+    pattern = BASE_PATTERN + r"(/manga/([^/?#]+))"
     example = "https://mangataro.org/manga/MANGA"
 
     def chapters(self, page):
@@ -75,7 +75,7 @@ class MangataroMangaExtractor(MangataroBase, MangaExtractor):
             results.append((url, {
                 **manga,
                 "chapter"      : text.parse_int(chapter),
-                "chapter_minor": f".{minor}" if sep else "",
+                "chapter_minor": "." + minor if sep else "",
                 "chapter_id"   : text.parse_int(chapter_id),
             }))
         return results
diff --git a/gallery_dl/extractor/mastodon.py b/gallery_dl/extractor/mastodon.py
index 165f8b82..cca15307 100644
--- a/gallery_dl/extractor/mastodon.py
+++ b/gallery_dl/extractor/mastodon.py
@@ -118,7 +118,7 @@ BASE_PATTERN = MastodonExtractor.update({
 class MastodonUserExtractor(MastodonExtractor):
     """Extractor for all images of an account/user"""
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/(?:@|users/)([^/?#]+)(?:/media)?/?$"
+    pattern = BASE_PATTERN + r"/(?:@|users/)([^/?#]+)(?:/media)?/?$"
     example = "https://mastodon.social/@USER"
 
     def statuses(self):
@@ -138,7 +138,7 @@ class MastodonUserExtractor(MastodonExtractor):
 class MastodonBookmarkExtractor(MastodonExtractor):
     """Extractor for mastodon bookmarks"""
     subcategory = "bookmark"
-    pattern = rf"{BASE_PATTERN}/bookmarks"
+    pattern = BASE_PATTERN + r"/bookmarks"
     example = "https://mastodon.social/bookmarks"
 
     def statuses(self):
@@ -148,7 +148,7 @@ class MastodonBookmarkExtractor(MastodonExtractor):
 class MastodonFavoriteExtractor(MastodonExtractor):
     """Extractor for mastodon favorites"""
     subcategory = "favorite"
-    pattern = rf"{BASE_PATTERN}/favourites"
+    pattern = BASE_PATTERN + r"/favourites"
     example = "https://mastodon.social/favourites"
 
     def statuses(self):
@@ -158,7 +158,7 @@ class MastodonFavoriteExtractor(MastodonExtractor):
 class MastodonListExtractor(MastodonExtractor):
     """Extractor for mastodon lists"""
     subcategory = "list"
-    pattern = rf"{BASE_PATTERN}/lists/(\w+)"
+    pattern = BASE_PATTERN + r"/lists/(\w+)"
     example = "https://mastodon.social/lists/12345"
 
     def statuses(self):
@@ -168,7 +168,7 @@ class MastodonListExtractor(MastodonExtractor):
 class MastodonHashtagExtractor(MastodonExtractor):
     """Extractor for mastodon hashtags"""
     subcategory = "hashtag"
-    pattern = rf"{BASE_PATTERN}/tags/(\w+)"
+    pattern = BASE_PATTERN + r"/tags/(\w+)"
     example = "https://mastodon.social/tags/NAME"
 
     def statuses(self):
@@ -178,7 +178,7 @@ class MastodonHashtagExtractor(MastodonExtractor):
 class MastodonFollowingExtractor(MastodonExtractor):
     """Extractor for followed mastodon users"""
     subcategory = "following"
-    pattern = rf"{BASE_PATTERN}/(?:@|users/)([^/?#]+)/following"
+    pattern = BASE_PATTERN + r"/(?:@|users/)([^/?#]+)/following"
     example = "https://mastodon.social/@USER/following"
 
     def items(self):
@@ -193,7 +193,7 @@ class MastodonFollowingExtractor(MastodonExtractor):
 class MastodonStatusExtractor(MastodonExtractor):
     """Extractor for images from a status"""
     subcategory = "status"
-    pattern = (rf"{BASE_PATTERN}/(?:@[^/?#]+|(?:users/[^/?#]+/)?"
+    pattern = (BASE_PATTERN + r"/(?:@[^/?#]+|(?:users/[^/?#]+/)?"
                r"(?:statuses|notice|objects()))/(?!following)([^/?#]+)")
     example = "https://mastodon.social/@USER/12345"
 
diff --git a/gallery_dl/extractor/misskey.py b/gallery_dl/extractor/misskey.py
index ca3ae185..f37bcada 100644
--- a/gallery_dl/extractor/misskey.py
+++ b/gallery_dl/extractor/misskey.py
@@ -102,7 +102,7 @@ BASE_PATTERN = MisskeyExtractor.update({
 class MisskeyUserExtractor(Dispatch, MisskeyExtractor):
     """Extractor for all images of a Misskey user"""
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/@([^/?#]+)/?$"
+    pattern = BASE_PATTERN + r"/@([^/?#]+)/?$"
     example = "https://misskey.io/@USER"
 
     def items(self):
@@ -118,7 +118,7 @@ class MisskeyUserExtractor(Dispatch, MisskeyExtractor):
 class MisskeyNotesExtractor(MisskeyExtractor):
     """Extractor for a Misskey user's notes"""
     subcategory = "notes"
-    pattern = rf"{BASE_PATTERN}/@([^/?#]+)/notes"
+    pattern = BASE_PATTERN + r"/@([^/?#]+)/notes"
     example = "https://misskey.io/@USER/notes"
 
     def notes(self):
@@ -129,7 +129,7 @@ class MisskeyNotesExtractor(MisskeyExtractor):
 class MisskeyInfoExtractor(MisskeyExtractor):
     """Extractor for a Misskey user's profile data"""
     subcategory = "info"
-    pattern = rf"{BASE_PATTERN}/@([^/?#]+)/info"
+    pattern = BASE_PATTERN + r"/@([^/?#]+)/info"
     example = "https://misskey.io/@USER/info"
 
     def items(self):
@@ -140,7 +140,7 @@ class MisskeyInfoExtractor(MisskeyExtractor):
 class MisskeyAvatarExtractor(MisskeyExtractor):
     """Extractor for a Misskey user's avatar"""
     subcategory = "avatar"
-    pattern = rf"{BASE_PATTERN}/@([^/?#]+)/avatar"
+    pattern = BASE_PATTERN + r"/@([^/?#]+)/avatar"
     example = "https://misskey.io/@USER/avatar"
 
     def notes(self):
@@ -152,7 +152,7 @@ class MisskeyAvatarExtractor(MisskeyExtractor):
 class MisskeyBackgroundExtractor(MisskeyExtractor):
     """Extractor for a Misskey user's banner image"""
     subcategory = "background"
-    pattern = rf"{BASE_PATTERN}/@([^/?#]+)/ba(?:nner|ckground)"
+    pattern = BASE_PATTERN + r"/@([^/?#]+)/ba(?:nner|ckground)"
     example = "https://misskey.io/@USER/banner"
 
     def notes(self):
@@ -164,7 +164,7 @@ class MisskeyBackgroundExtractor(MisskeyExtractor):
 class MisskeyFollowingExtractor(MisskeyExtractor):
     """Extractor for followed Misskey users"""
     subcategory = "following"
-    pattern = rf"{BASE_PATTERN}/@([^/?#]+)/following"
+    pattern = BASE_PATTERN + r"/@([^/?#]+)/following"
     example = "https://misskey.io/@USER/following"
 
     def items(self):
@@ -181,7 +181,7 @@ class MisskeyFollowingExtractor(MisskeyExtractor):
 class MisskeyNoteExtractor(MisskeyExtractor):
     """Extractor for images from a Note"""
     subcategory = "note"
-    pattern = rf"{BASE_PATTERN}/notes/(\w+)"
+    pattern = BASE_PATTERN + r"/notes/(\w+)"
     example = "https://misskey.io/notes/98765"
 
     def notes(self):
@@ -191,7 +191,7 @@ class MisskeyNoteExtractor(MisskeyExtractor):
 class MisskeyFavoriteExtractor(MisskeyExtractor):
     """Extractor for favorited notes"""
     subcategory = "favorite"
-    pattern = rf"{BASE_PATTERN}/(?:my|api/i)/favorites"
+    pattern = BASE_PATTERN + r"/(?:my|api/i)/favorites"
     example = "https://misskey.io/my/favorites"
 
     def notes(self):
diff --git a/gallery_dl/extractor/moebooru.py b/gallery_dl/extractor/moebooru.py
index 23f8fd95..083c4215 100644
--- a/gallery_dl/extractor/moebooru.py
+++ b/gallery_dl/extractor/moebooru.py
@@ -92,7 +92,7 @@ class MoebooruTagExtractor(MoebooruExtractor):
     subcategory = "tag"
     directory_fmt = ("{category}", "{search_tags}")
     archive_fmt = "t_{search_tags}_{id}"
-    pattern = rf"{BASE_PATTERN}/post\?(?:[^&#]*&)*tags=([^&#]*)"
+    pattern = BASE_PATTERN + r"/post\?(?:[^&#]*&)*tags=([^&#]*)"
     example = "https://yande.re/post?tags=TAG"
 
     def __init__(self, match):
@@ -104,14 +104,14 @@ class MoebooruTagExtractor(MoebooruExtractor):
 
     def posts(self):
         params = {"tags": self.tags}
-        return self._pagination(f"{self.root}/post.json", params)
+        return self._pagination(self.root + "/post.json", params)
 
 
 class MoebooruPoolExtractor(MoebooruExtractor):
     subcategory = "pool"
     directory_fmt = ("{category}", "pool", "{pool}")
     archive_fmt = "p_{pool}_{id}"
-    pattern = rf"{BASE_PATTERN}/pool/show/(\d+)"
+    pattern = BASE_PATTERN + r"/pool/show/(\d+)"
     example = "https://yande.re/pool/show/12345"
 
     def __init__(self, match):
@@ -129,26 +129,26 @@ class MoebooruPoolExtractor(MoebooruExtractor):
 
     def posts(self):
         params = {"tags": "pool:" + self.pool_id}
-        return self._pagination(f"{self.root}/post.json", params)
+        return self._pagination(self.root + "/post.json", params)
 
 
 class MoebooruPostExtractor(MoebooruExtractor):
     subcategory = "post"
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}/post/show/(\d+)"
+    pattern = BASE_PATTERN + r"/post/show/(\d+)"
     example = "https://yande.re/post/show/12345"
 
     def posts(self):
         params = {"tags": "id:" + self.groups[-1]}
-        return self.request_json(f"{self.root}/post.json", params=params)
+        return self.request_json(self.root + "/post.json", params=params)
 
 
 class MoebooruPopularExtractor(MoebooruExtractor):
     subcategory = "popular"
     directory_fmt = ("{category}", "popular", "{scale}", "{date}")
     archive_fmt = "P_{scale[0]}_{date}_{id}"
-    pattern = (rf"{BASE_PATTERN}"
-               rf"/post/popular_(by_(?:day|week|month)|recent)(?:\?([^#]*))?")
+    pattern = BASE_PATTERN + \
+        r"/post/popular_(by_(?:day|week|month)|recent)(?:\?([^#]*))?"
     example = "https://yande.re/post/popular_by_month?year=YYYY&month=MM"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/motherless.py b/gallery_dl/extractor/motherless.py
index c20f138f..7d5d3197 100644
--- a/gallery_dl/extractor/motherless.py
+++ b/gallery_dl/extractor/motherless.py
@@ -93,8 +93,8 @@ class MotherlessExtractor(Extractor):
             title = self._extract_group_title(page, gid)
 
         return {
-            f"{category}_id": gid,
-            f"{category}_title": title,
+            category + "_id": gid,
+            category + "_title": title,
             "uploader": text.remove_html(extr(
                 f'class="{category}-member-username">', "</")),
             "count": text.parse_int(
@@ -152,9 +152,9 @@ class MotherlessExtractor(Extractor):
 class MotherlessMediaExtractor(MotherlessExtractor):
     """Extractor for a single image/video from motherless.com"""
     subcategory = "media"
-    pattern = (rf"{BASE_PATTERN}/("
-               rf"(?:g/[^/?#]+/|G[IV]?[A-Z0-9]+/)?"
-               rf"(?!G)[A-Z0-9]+)")
+    pattern = (BASE_PATTERN +
+               r"/((?:g/[^/?#]+/|G[IV]?[A-Z0-9]+/)?"
+               r"(?!G)[A-Z0-9]+)")
     example = "https://motherless.com/ABC123"
 
     def items(self):
@@ -170,7 +170,7 @@ class MotherlessGalleryExtractor(MotherlessExtractor):
     directory_fmt = ("{category}", "{uploader}",
                      "{gallery_id} {gallery_title}")
     archive_fmt = "{gallery_id}_{id}"
-    pattern = rf"{BASE_PATTERN}/G([IVG])?([A-Z0-9]+)/?$"
+    pattern = BASE_PATTERN + "/G([IVG])?([A-Z0-9]+)/?$"
     example = "https://motherless.com/GABC123"
 
     def items(self):
@@ -206,7 +206,7 @@ class MotherlessGroupExtractor(MotherlessExtractor):
     directory_fmt = ("{category}", "{uploader}",
                      "{group_id} {group_title}")
     archive_fmt = "{group_id}_{id}"
-    pattern = rf"{BASE_PATTERN}/g([iv]?)/?([a-z0-9_]+)/?$"
+    pattern = BASE_PATTERN + "/g([iv]?)/?([a-z0-9_]+)/?$"
     example = "https://motherless.com/g/abc123"
 
     def items(self):
diff --git a/gallery_dl/extractor/myhentaigallery.py b/gallery_dl/extractor/myhentaigallery.py
index 936f857a..b94a73f4 100644
--- a/gallery_dl/extractor/myhentaigallery.py
+++ b/gallery_dl/extractor/myhentaigallery.py
@@ -20,7 +20,7 @@ class MyhentaigalleryBase():
 class MyhentaigalleryGalleryExtractor(MyhentaigalleryBase, GalleryExtractor):
     """Extractor for image galleries from myhentaigallery.com"""
     directory_fmt = ("{category}", "{gallery_id} {artist:?[/] /J, }{title}")
-    pattern = rf"{BASE_PATTERN}/g(?:allery/(?:thumbnails|show))?/(\d+)"
+    pattern = BASE_PATTERN + r"/g(?:allery/(?:thumbnails|show))?/(\d+)"
     example = "https://myhentaigallery.com/g/12345"
 
     def __init__(self, match):
@@ -62,7 +62,7 @@ class MyhentaigalleryGalleryExtractor(MyhentaigalleryBase, GalleryExtractor):
 class MyhentaigalleryTagExtractor(MyhentaigalleryBase, Extractor):
     """Extractor for myhentaigallery tag searches"""
     subcategory = "tag"
-    pattern = rf"{BASE_PATTERN}(/g/(artist|category|group|parody)/(\d+).*)"
+    pattern = BASE_PATTERN + r"(/g/(artist|category|group|parody)/(\d+).*)"
     example = "https://myhentaigallery.com/g/category/123"
 
     def items(self):
diff --git a/gallery_dl/extractor/naverblog.py b/gallery_dl/extractor/naverblog.py
index cc96e099..24707f78 100644
--- a/gallery_dl/extractor/naverblog.py
+++ b/gallery_dl/extractor/naverblog.py
@@ -142,7 +142,7 @@ class NaverBlogBlogExtractor(NaverBlogBase, Extractor):
         )
 
         # setup params for API calls
-        url = f"{self.root}/PostViewBottomTitleListAsync.nhn"
+        url = self.root + "/PostViewBottomTitleListAsync.nhn"
         params = {
             "blogId"             : self.blog_id,
             "logNo"              : post_num or "0",
diff --git a/gallery_dl/extractor/naverwebtoon.py b/gallery_dl/extractor/naverwebtoon.py
index 72089d01..3211941c 100644
--- a/gallery_dl/extractor/naverwebtoon.py
+++ b/gallery_dl/extractor/naverwebtoon.py
@@ -27,7 +27,7 @@ class NaverWebtoonEpisodeExtractor(NaverWebtoonBase, GalleryExtractor):
     directory_fmt = ("{category}", "{comic}")
     filename_fmt = "{episode:>03}-{num:>02}.{extension}"
     archive_fmt = "{title_id}_{episode}_{num}"
-    pattern = rf"{BASE_PATTERN}/detail(?:\.nhn)?\?([^#]+)"
+    pattern = BASE_PATTERN + r"/detail(?:\.nhn)?\?([^#]+)"
     example = "https://comic.naver.com/webtoon/detail?titleId=12345&no=1"
 
     def __init__(self, match):
@@ -66,7 +66,7 @@ class NaverWebtoonEpisodeExtractor(NaverWebtoonBase, GalleryExtractor):
 class NaverWebtoonComicExtractor(NaverWebtoonBase, Extractor):
     subcategory = "comic"
     categorytransfer = True
-    pattern = rf"{BASE_PATTERN}/list(?:\.nhn)?\?([^#]+)"
+    pattern = BASE_PATTERN + r"/list(?:\.nhn)?\?([^#]+)"
     example = "https://comic.naver.com/webtoon/list?titleId=12345"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/nekohouse.py b/gallery_dl/extractor/nekohouse.py
index 728912b4..8de2951e 100644
--- a/gallery_dl/extractor/nekohouse.py
+++ b/gallery_dl/extractor/nekohouse.py
@@ -12,7 +12,7 @@ from .common import Extractor, Message
 from .. import text
 
 BASE_PATTERN = r"(?:https?://)?nekohouse\.su"
-USER_PATTERN = rf"{BASE_PATTERN}/([^/?#]+)/user/([^/?#]+)"
+USER_PATTERN = BASE_PATTERN + r"/([^/?#]+)/user/([^/?#]+)"
 
 
 class NekohouseExtractor(Extractor):
@@ -27,7 +27,7 @@ class NekohousePostExtractor(NekohouseExtractor):
                      "{post_id} {date} {title[b:230]}")
     filename_fmt = "{num:>02} {id|filename}.{extension}"
     archive_fmt = "{service}_{user_id}_{post_id}_{hash}"
-    pattern = rf"{USER_PATTERN}/post/([^/?#]+)"
+    pattern = USER_PATTERN + r"/post/([^/?#]+)"
     example = "https://nekohouse.su/SERVICE/user/12345/post/12345"
 
     def items(self):
@@ -98,7 +98,7 @@ class NekohousePostExtractor(NekohouseExtractor):
 
 class NekohouseUserExtractor(NekohouseExtractor):
     subcategory = "user"
-    pattern = rf"{USER_PATTERN}/?(?:\?([^#]+))?(?:$|\?|#)"
+    pattern = USER_PATTERN + r"/?(?:\?([^#]+))?(?:$|\?|#)"
     example = "https://nekohouse.su/SERVICE/user/12345"
 
     def items(self):
diff --git a/gallery_dl/extractor/newgrounds.py b/gallery_dl/extractor/newgrounds.py
index f980f4b5..f1a07b3e 100644
--- a/gallery_dl/extractor/newgrounds.py
+++ b/gallery_dl/extractor/newgrounds.py
@@ -412,7 +412,7 @@ class NewgroundsImageExtractor(NewgroundsExtractor):
 class NewgroundsMediaExtractor(NewgroundsExtractor):
     """Extractor for a media file from newgrounds.com"""
     subcategory = "media"
-    pattern = rf"{BASE_PATTERN}(/(?:portal/view|audio/listen)/\d+)"
+    pattern = BASE_PATTERN + r"(/(?:portal/view|audio/listen)/\d+)"
     example = "https://www.newgrounds.com/portal/view/12345"
 
     def __init__(self, match):
@@ -427,34 +427,34 @@ class NewgroundsMediaExtractor(NewgroundsExtractor):
 class NewgroundsArtExtractor(NewgroundsExtractor):
     """Extractor for all images of a newgrounds user"""
     subcategory = _path = "art"
-    pattern = rf"{USER_PATTERN}/art(?:(?:/page/|/?\?page=)(\d+))?/?$"
+    pattern = USER_PATTERN + r"/art(?:(?:/page/|/?\?page=)(\d+))?/?$"
     example = "https://USER.newgrounds.com/art"
 
 
 class NewgroundsAudioExtractor(NewgroundsExtractor):
     """Extractor for all audio submissions of a newgrounds user"""
     subcategory = _path = "audio"
-    pattern = rf"{USER_PATTERN}/audio(?:(?:/page/|/?\?page=)(\d+))?/?$"
+    pattern = USER_PATTERN + r"/audio(?:(?:/page/|/?\?page=)(\d+))?/?$"
     example = "https://USER.newgrounds.com/audio"
 
 
 class NewgroundsMoviesExtractor(NewgroundsExtractor):
     """Extractor for all movies of a newgrounds user"""
     subcategory = _path = "movies"
-    pattern = rf"{USER_PATTERN}/movies(?:(?:/page/|/?\?page=)(\d+))?/?$"
+    pattern = USER_PATTERN + r"/movies(?:(?:/page/|/?\?page=)(\d+))?/?$"
     example = "https://USER.newgrounds.com/movies"
 
 
 class NewgroundsGamesExtractor(NewgroundsExtractor):
     """Extractor for a newgrounds user's games"""
     subcategory = _path = "games"
-    pattern = rf"{USER_PATTERN}/games(?:(?:/page/|/?\?page=)(\d+))?/?$"
+    pattern = USER_PATTERN + r"/games(?:(?:/page/|/?\?page=)(\d+))?/?$"
     example = "https://USER.newgrounds.com/games"
 
 
 class NewgroundsUserExtractor(Dispatch, NewgroundsExtractor):
     """Extractor for a newgrounds user profile"""
-    pattern = rf"{USER_PATTERN}/?$"
+    pattern = USER_PATTERN + r"/?$"
     example = "https://USER.newgrounds.com"
 
     def items(self):
@@ -471,7 +471,7 @@ class NewgroundsFavoriteExtractor(NewgroundsExtractor):
     """Extractor for posts favorited by a newgrounds user"""
     subcategory = "favorite"
     directory_fmt = ("{category}", "{user}", "Favorites")
-    pattern = (rf"{USER_PATTERN}/favorites(?!/following)(?:/(art|audio|movies)"
+    pattern = (USER_PATTERN + r"/favorites(?!/following)(?:/(art|audio|movies)"
                r"(?:(?:/page/|/?\?page=)(\d+))?)?")
     example = "https://USER.newgrounds.com/favorites"
 
@@ -510,16 +510,15 @@ class NewgroundsFavoriteExtractor(NewgroundsExtractor):
     def _extract_favorites(self, page):
         return [
             self.root + path
-            for path in text.extract_iter(page, f'href="{self.root}', '"')
+            for path in text.extract_iter(page, 'href="' + self.root, '"')
         ]
 
 
 class NewgroundsFollowingExtractor(NewgroundsFavoriteExtractor):
     """Extractor for a newgrounds user's favorited users"""
     subcategory = "following"
-    pattern = (rf"{USER_PATTERN}/favorites/(following)"
+    pattern = (USER_PATTERN + r"/favorites/(following)"
                r"(?:(?:/page/|/?\?page=)(\d+))?")
-
     example = "https://USER.newgrounds.com/favorites/following"
 
     def items(self):
@@ -539,7 +538,7 @@ class NewgroundsSearchExtractor(NewgroundsExtractor):
     """Extractor for newgrounds.com search reesults"""
     subcategory = "search"
     directory_fmt = ("{category}", "search", "{search_tags}")
-    pattern = rf"{BASE_PATTERN}/search/conduct/([^/?#]+)/?\?([^#]+)"
+    pattern = BASE_PATTERN + r"/search/conduct/([^/?#]+)/?\?([^#]+)"
     example = "https://www.newgrounds.com/search/conduct/art?terms=QUERY"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/nijie.py b/gallery_dl/extractor/nijie.py
index a6b01c2f..181d54d6 100644
--- a/gallery_dl/extractor/nijie.py
+++ b/gallery_dl/extractor/nijie.py
@@ -140,7 +140,7 @@ class NijieExtractor(AsynchronousMixin, BaseExtractor):
     def _login_impl(self, username, password):
         self.log.info("Logging in as %s", username)
 
-        url = f"{self.root}/login_int.php"
+        url = self.root + "/login_int.php"
         data = {"email": username, "password": password, "save": "on"}
 
         response = self.request(url, method="POST", data=data)
@@ -178,7 +178,7 @@ BASE_PATTERN = NijieExtractor.update({
 
 class NijieUserExtractor(Dispatch, NijieExtractor):
     """Extractor for nijie user profiles"""
-    pattern = rf"{BASE_PATTERN}/members\.php\?id=(\d+)"
+    pattern = BASE_PATTERN + r"/members\.php\?id=(\d+)"
     example = "https://nijie.info/members.php?id=12345"
 
     def items(self):
@@ -194,7 +194,7 @@ class NijieUserExtractor(Dispatch, NijieExtractor):
 class NijieIllustrationExtractor(NijieExtractor):
     """Extractor for all illustrations of a nijie-user"""
     subcategory = "illustration"
-    pattern = rf"{BASE_PATTERN}/members_illust\.php\?id=(\d+)"
+    pattern = BASE_PATTERN + r"/members_illust\.php\?id=(\d+)"
     example = "https://nijie.info/members_illust.php?id=12345"
 
     def image_ids(self):
@@ -204,7 +204,7 @@ class NijieIllustrationExtractor(NijieExtractor):
 class NijieDoujinExtractor(NijieExtractor):
     """Extractor for doujin entries of a nijie user"""
     subcategory = "doujin"
-    pattern = rf"{BASE_PATTERN}/members_dojin\.php\?id=(\d+)"
+    pattern = BASE_PATTERN + r"/members_dojin\.php\?id=(\d+)"
     example = "https://nijie.info/members_dojin.php?id=12345"
 
     def image_ids(self):
@@ -216,7 +216,7 @@ class NijieFavoriteExtractor(NijieExtractor):
     subcategory = "favorite"
     directory_fmt = ("{category}", "bookmarks", "{user_id}")
     archive_fmt = "f_{user_id}_{image_id}_{num}"
-    pattern = rf"{BASE_PATTERN}/user_like_illust_view\.php\?id=(\d+)"
+    pattern = BASE_PATTERN + r"/user_like_illust_view\.php\?id=(\d+)"
     example = "https://nijie.info/user_like_illust_view.php?id=12345"
 
     def image_ids(self):
@@ -234,7 +234,7 @@ class NijieNuitaExtractor(NijieExtractor):
     subcategory = "nuita"
     directory_fmt = ("{category}", "nuita", "{user_id}")
     archive_fmt = "n_{user_id}_{image_id}_{num}"
-    pattern = rf"{BASE_PATTERN}/history_nuita\.php\?id=(\d+)"
+    pattern = BASE_PATTERN + r"/history_nuita\.php\?id=(\d+)"
     example = "https://nijie.info/history_nuita.php?id=12345"
 
     def image_ids(self):
@@ -253,7 +253,7 @@ class NijieNuitaExtractor(NijieExtractor):
 class NijieFeedExtractor(NijieExtractor):
     """Extractor for nijie liked user feed"""
     subcategory = "feed"
-    pattern = rf"{BASE_PATTERN}/like_user_view\.php"
+    pattern = BASE_PATTERN + r"/like_user_view\.php"
     example = "https://nijie.info/like_user_view.php"
 
     def image_ids(self):
@@ -266,7 +266,7 @@ class NijieFeedExtractor(NijieExtractor):
 class NijieFollowedExtractor(NijieExtractor):
     """Extractor for followed nijie users"""
     subcategory = "followed"
-    pattern = rf"{BASE_PATTERN}/like_my\.php"
+    pattern = BASE_PATTERN + r"/like_my\.php"
     example = "https://nijie.info/like_my.php"
 
     def items(self):
@@ -292,7 +292,7 @@ class NijieFollowedExtractor(NijieExtractor):
 class NijieImageExtractor(NijieExtractor):
     """Extractor for a nijie work/image"""
     subcategory = "image"
-    pattern = rf"{BASE_PATTERN}/view(?:_popup)?\.php\?id=(\d+)"
+    pattern = BASE_PATTERN + r"/view(?:_popup)?\.php\?id=(\d+)"
     example = "https://nijie.info/view.php?id=12345"
 
     def image_ids(self):
diff --git a/gallery_dl/extractor/nitter.py b/gallery_dl/extractor/nitter.py
index 321883cd..cf463b29 100644
--- a/gallery_dl/extractor/nitter.py
+++ b/gallery_dl/extractor/nitter.py
@@ -229,12 +229,12 @@ class NitterExtractor(BaseExtractor):
 BASE_PATTERN = NitterExtractor.update({
 })
 
-USER_PATTERN = rf"{BASE_PATTERN}/(i(?:/user/|d:)(\d+)|[^/?#]+)"
+USER_PATTERN = BASE_PATTERN + r"/(i(?:/user/|d:)(\d+)|[^/?#]+)"
 
 
 class NitterTweetsExtractor(NitterExtractor):
     subcategory = "tweets"
-    pattern = rf"{USER_PATTERN}(?:/tweets)?(?:$|\?|#)"
+    pattern = USER_PATTERN + r"(?:/tweets)?(?:$|\?|#)"
     example = "https://nitter.net/USER"
 
     def tweets(self):
@@ -243,7 +243,7 @@ class NitterTweetsExtractor(NitterExtractor):
 
 class NitterRepliesExtractor(NitterExtractor):
     subcategory = "replies"
-    pattern = rf"{USER_PATTERN}/with_replies"
+    pattern = USER_PATTERN + r"/with_replies"
     example = "https://nitter.net/USER/with_replies"
 
     def tweets(self):
@@ -252,7 +252,7 @@ class NitterRepliesExtractor(NitterExtractor):
 
 class NitterMediaExtractor(NitterExtractor):
     subcategory = "media"
-    pattern = rf"{USER_PATTERN}/media"
+    pattern = USER_PATTERN + r"/media"
     example = "https://nitter.net/USER/media"
 
     def tweets(self):
@@ -261,7 +261,7 @@ class NitterMediaExtractor(NitterExtractor):
 
 class NitterSearchExtractor(NitterExtractor):
     subcategory = "search"
-    pattern = rf"{USER_PATTERN}/search"
+    pattern = USER_PATTERN + r"/search"
     example = "https://nitter.net/USER/search"
 
     def tweets(self):
@@ -274,7 +274,7 @@ class NitterTweetExtractor(NitterExtractor):
     directory_fmt = ("{category}", "{user[name]}")
     filename_fmt = "{tweet_id}_{num}.{extension}"
     archive_fmt = "{tweet_id}_{num}"
-    pattern = rf"{BASE_PATTERN}/(i/web|[^/?#]+)/status/(\d+())"
+    pattern = BASE_PATTERN + r"/(i/web|[^/?#]+)/status/(\d+())"
     example = "https://nitter.net/USER/status/12345"
 
     def tweets(self):
diff --git a/gallery_dl/extractor/nudostar.py b/gallery_dl/extractor/nudostar.py
index 2eb43401..d0128c0e 100644
--- a/gallery_dl/extractor/nudostar.py
+++ b/gallery_dl/extractor/nudostar.py
@@ -21,7 +21,7 @@ class NudostarExtractor(GalleryExtractor):
 class NudostarModelExtractor(NudostarExtractor):
     """Extractor for NudoStar models"""
     subcategory = "model"
-    pattern = rf"{BASE_PATTERN}(/models/([^/?#]+)/?)$"
+    pattern = BASE_PATTERN + r"(/models/([^/?#]+)/?)$"
     example = "https://nudostar.tv/models/MODEL/"
 
     def metadata(self, page):
@@ -53,7 +53,7 @@ class NudostarModelExtractor(NudostarExtractor):
 class NudostarImageExtractor(NudostarExtractor):
     """Extractor for NudoStar images"""
     subcategory = "image"
-    pattern = rf"{BASE_PATTERN}(/models/([^/?#]+)/(\d+)/)"
+    pattern = BASE_PATTERN + r"(/models/([^/?#]+)/(\d+)/)"
     example = "https://nudostar.tv/models/MODEL/123/"
 
     def items(self):
diff --git a/gallery_dl/extractor/paheal.py b/gallery_dl/extractor/paheal.py
index d56331f7..be22dea5 100644
--- a/gallery_dl/extractor/paheal.py
+++ b/gallery_dl/extractor/paheal.py
@@ -97,7 +97,7 @@ class PahealTagExtractor(PahealExtractor):
 
         while True:
             try:
-                page = self.request(f"{base}{pnum}").text
+                page = self.request(base + str(pnum)).text
             except exception.HttpError as exc:
                 if exc.status == 404:
                     return
diff --git a/gallery_dl/extractor/patreon.py b/gallery_dl/extractor/patreon.py
index 12dfd48e..cdfda0f2 100644
--- a/gallery_dl/extractor/patreon.py
+++ b/gallery_dl/extractor/patreon.py
@@ -300,8 +300,8 @@ class PatreonExtractor(Extractor):
                 order = "-published_at"
             elif order in {"a", "asc", "r", "reverse"}:
                 order = "published_at"
-            return f"&sort={order}"
-        return f"&sort={sort}" if sort else ""
+            return "&sort=" + order
+        return "&sort=" + sort if sort else ""
 
     def _build_file_generators(self, filetypes):
         if filetypes is None:
@@ -382,8 +382,8 @@ class PatreonCollectionExtractor(PatreonExtractor):
             elif order in {"d", "desc", "r", "reverse"}:
                 # "-collection_order" results in a '400 Bad Request' error
                 order = "-published_at"
-            return f"&sort={order}"
-        return f"&sort={sort}" if sort else ""
+            return "&sort=" + order
+        return "&sort=" + sort if sort else ""
 
 
 class PatreonCreatorExtractor(PatreonExtractor):
diff --git a/gallery_dl/extractor/pexels.py b/gallery_dl/extractor/pexels.py
index 9e2f40cb..5f4ebc72 100644
--- a/gallery_dl/extractor/pexels.py
+++ b/gallery_dl/extractor/pexels.py
@@ -62,7 +62,7 @@ class PexelsCollectionExtractor(PexelsExtractor):
     """Extractor for a pexels.com collection"""
     subcategory = "collection"
     directory_fmt = ("{category}", "Collections", "{collection}")
-    pattern = rf"{BASE_PATTERN}/collections/((?:[^/?#]*-)?(\w+))"
+    pattern = BASE_PATTERN + r"/collections/((?:[^/?#]*-)?(\w+))"
     example = "https://www.pexels.com/collections/SLUG-a1b2c3/"
 
     def metadata(self):
@@ -77,7 +77,7 @@ class PexelsSearchExtractor(PexelsExtractor):
     """Extractor for pexels.com search results"""
     subcategory = "search"
     directory_fmt = ("{category}", "Searches", "{search_tags}")
-    pattern = rf"{BASE_PATTERN}/search/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/search/([^/?#]+)"
     example = "https://www.pexels.com/search/QUERY/"
 
     def metadata(self):
@@ -91,7 +91,7 @@ class PexelsUserExtractor(PexelsExtractor):
     """Extractor for pexels.com user galleries"""
     subcategory = "user"
     directory_fmt = ("{category}", "@{user[slug]}")
-    pattern = rf"{BASE_PATTERN}/(@(?:(?:[^/?#]*-)?(\d+)|[^/?#]+))"
+    pattern = BASE_PATTERN + r"/(@(?:(?:[^/?#]*-)?(\d+)|[^/?#]+))"
     example = "https://www.pexels.com/@USER-12345/"
 
     def posts(self):
@@ -100,7 +100,7 @@ class PexelsUserExtractor(PexelsExtractor):
 
 class PexelsImageExtractor(PexelsExtractor):
     subcategory = "image"
-    pattern = rf"{BASE_PATTERN}/photo/((?:[^/?#]*-)?\d+)"
+    pattern = BASE_PATTERN + r"/photo/((?:[^/?#]*-)?\d+)"
     example = "https://www.pexels.com/photo/SLUG-12345/"
 
     def posts(self):
diff --git a/gallery_dl/extractor/philomena.py b/gallery_dl/extractor/philomena.py
index 3634c667..2f52b9ab 100644
--- a/gallery_dl/extractor/philomena.py
+++ b/gallery_dl/extractor/philomena.py
@@ -61,7 +61,7 @@ BASE_PATTERN = PhilomenaExtractor.update({
 class PhilomenaPostExtractor(PhilomenaExtractor):
     """Extractor for single posts on a Philomena booru"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/(?:images/)?(\d+)"
+    pattern = BASE_PATTERN + r"/(?:images/)?(\d+)"
     example = "https://derpibooru.org/images/12345"
 
     def posts(self):
@@ -72,7 +72,7 @@ class PhilomenaSearchExtractor(PhilomenaExtractor):
     """Extractor for Philomena search results"""
     subcategory = "search"
     directory_fmt = ("{category}", "{search_tags}")
-    pattern = rf"{BASE_PATTERN}/(?:search/?\?([^#]+)|tags/([^/?#]+))"
+    pattern = BASE_PATTERN + r"/(?:search/?\?([^#]+)|tags/([^/?#]+))"
     example = "https://derpibooru.org/search?q=QUERY"
 
     def __init__(self, match):
@@ -106,7 +106,7 @@ class PhilomenaGalleryExtractor(PhilomenaExtractor):
     subcategory = "gallery"
     directory_fmt = ("{category}", "galleries",
                      "{gallery[id]} {gallery[title]}")
-    pattern = rf"{BASE_PATTERN}/galleries/(\d+)"
+    pattern = BASE_PATTERN + r"/galleries/(\d+)"
     example = "https://derpibooru.org/galleries/12345"
 
     def metadata(self):
@@ -116,7 +116,7 @@ class PhilomenaGalleryExtractor(PhilomenaExtractor):
             raise exception.NotFoundError("gallery")
 
     def posts(self):
-        gallery_id = f"gallery_id:{self.groups[-1]}"
+        gallery_id = "gallery_id:" + self.groups[-1]
         params = {"sd": "desc", "sf": gallery_id, "q": gallery_id}
         return self.api.search(params)
 
diff --git a/gallery_dl/extractor/photovogue.py b/gallery_dl/extractor/photovogue.py
index cb16b232..8559a109 100644
--- a/gallery_dl/extractor/photovogue.py
+++ b/gallery_dl/extractor/photovogue.py
@@ -18,7 +18,7 @@ class PhotovogueUserExtractor(Extractor):
     directory_fmt = ("{category}", "{photographer[id]} {photographer[name]}")
     filename_fmt = "{id} {title}.{extension}"
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}/photographers/(\d+)"
+    pattern = BASE_PATTERN + r"/photographers/(\d+)"
     example = "https://www.vogue.com/photovogue/photographers/12345"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/pictoa.py b/gallery_dl/extractor/pictoa.py
index 0dfe304d..e358541e 100644
--- a/gallery_dl/extractor/pictoa.py
+++ b/gallery_dl/extractor/pictoa.py
@@ -24,7 +24,7 @@ class PictoaExtractor(Extractor):
 class PictoaImageExtractor(PictoaExtractor):
     """Extractor for single images from pictoa.com"""
     subcategory = "image"
-    pattern = rf"{BASE_PATTERN}/albums/(?:[\w-]+-)?(\d+)/(\d+)"
+    pattern = BASE_PATTERN + r"/albums/(?:[\w-]+-)?(\d+)/(\d+)"
     example = "https://www.pictoa.com/albums/NAME-12345/12345.html"
 
     def items(self):
@@ -50,7 +50,7 @@ class PictoaImageExtractor(PictoaExtractor):
 class PictoaAlbumExtractor(PictoaExtractor):
     """Extractor for image albums from pictoa.com"""
     subcategory = "album"
-    pattern = rf"{BASE_PATTERN}/albums/(?:[\w-]+-)?(\d+).html"
+    pattern = BASE_PATTERN + r"/albums/(?:[\w-]+-)?(\d+).html"
     example = "https://www.pictoa.com/albums/NAME-12345.html"
 
     def items(self):
diff --git a/gallery_dl/extractor/piczel.py b/gallery_dl/extractor/piczel.py
index 6661e7d2..ccb6aa69 100644
--- a/gallery_dl/extractor/piczel.py
+++ b/gallery_dl/extractor/piczel.py
@@ -66,7 +66,7 @@ class PiczelExtractor(Extractor):
 class PiczelUserExtractor(PiczelExtractor):
     """Extractor for all images from a user's gallery"""
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/gallery/([^/?#]+)/?$"
+    pattern = BASE_PATTERN + r"/gallery/([^/?#]+)/?$"
     example = "https://piczel.tv/gallery/USER"
 
     def posts(self):
@@ -79,7 +79,7 @@ class PiczelFolderExtractor(PiczelExtractor):
     subcategory = "folder"
     directory_fmt = ("{category}", "{user[username]}", "{folder[name]}")
     archive_fmt = "f{folder[id]}_{id}_{num}"
-    pattern = rf"{BASE_PATTERN}/gallery/(?!image/)[^/?#]+/(\d+)"
+    pattern = BASE_PATTERN + r"/gallery/(?!image/)[^/?#]+/(\d+)"
     example = "https://piczel.tv/gallery/USER/12345"
 
     def posts(self):
@@ -90,7 +90,7 @@ class PiczelFolderExtractor(PiczelExtractor):
 class PiczelImageExtractor(PiczelExtractor):
     """Extractor for individual images"""
     subcategory = "image"
-    pattern = rf"{BASE_PATTERN}/gallery/image/(\d+)"
+    pattern = BASE_PATTERN + r"/gallery/image/(\d+)"
     example = "https://piczel.tv/gallery/image/12345"
 
     def posts(self):
diff --git a/gallery_dl/extractor/pillowfort.py b/gallery_dl/extractor/pillowfort.py
index 0b750fe8..570ed85a 100644
--- a/gallery_dl/extractor/pillowfort.py
+++ b/gallery_dl/extractor/pillowfort.py
@@ -119,7 +119,7 @@ class PillowfortExtractor(Extractor):
 class PillowfortPostExtractor(PillowfortExtractor):
     """Extractor for a single pillowfort post"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/posts/(\d+)"
+    pattern = BASE_PATTERN + r"/posts/(\d+)"
     example = "https://www.pillowfort.social/posts/12345"
 
     def posts(self):
@@ -130,7 +130,7 @@ class PillowfortPostExtractor(PillowfortExtractor):
 class PillowfortUserExtractor(PillowfortExtractor):
     """Extractor for all posts of a pillowfort user"""
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/(?!posts/)([^/?#]+(?:/tagged/[^/?#]+)?)"
+    pattern = BASE_PATTERN + r"/(?!posts/)([^/?#]+(?:/tagged/[^/?#]+)?)"
     example = "https://www.pillowfort.social/USER"
 
     def posts(self):
diff --git a/gallery_dl/extractor/pinterest.py b/gallery_dl/extractor/pinterest.py
index 7aa32ec7..cd3d077c 100644
--- a/gallery_dl/extractor/pinterest.py
+++ b/gallery_dl/extractor/pinterest.py
@@ -207,7 +207,7 @@ class PinterestExtractor(Extractor):
 class PinterestUserExtractor(PinterestExtractor):
     """Extractor for a user's boards"""
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/(?!pin/)([^/?#]+)(?:/_saved)?/?$"
+    pattern = BASE_PATTERN + r"/(?!pin/)([^/?#]+)(?:/_saved)?/?$"
     example = "https://www.pinterest.com/USER/"
 
     def __init__(self, match):
@@ -225,7 +225,7 @@ class PinterestAllpinsExtractor(PinterestExtractor):
     """Extractor for a user's 'All Pins' feed"""
     subcategory = "allpins"
     directory_fmt = ("{category}", "{user}")
-    pattern = rf"{BASE_PATTERN}/(?!pin/)([^/?#]+)/pins/?$"
+    pattern = BASE_PATTERN + r"/(?!pin/)([^/?#]+)/pins/?$"
     example = "https://www.pinterest.com/USER/pins/"
 
     def __init__(self, match):
@@ -243,7 +243,7 @@ class PinterestCreatedExtractor(PinterestExtractor):
     """Extractor for a user's created pins"""
     subcategory = "created"
     directory_fmt = ("{category}", "{user}")
-    pattern = rf"{BASE_PATTERN}/(?!pin/)([^/?#]+)/_created/?$"
+    pattern = BASE_PATTERN + r"/(?!pin/)([^/?#]+)/_created/?$"
     example = "https://www.pinterest.com/USER/_created/"
 
     def __init__(self, match):
@@ -263,7 +263,7 @@ class PinterestSectionExtractor(PinterestExtractor):
     directory_fmt = ("{category}", "{board[owner][username]}",
                      "{board[name]}", "{section[title]}")
     archive_fmt = "{board[id]}_{id}"
-    pattern = rf"{BASE_PATTERN}/(?!pin/)([^/?#]+)/([^/?#]+)/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/(?!pin/)([^/?#]+)/([^/?#]+)/([^/?#]+)"
     example = "https://www.pinterest.com/USER/BOARD/SECTION"
 
     def __init__(self, match):
@@ -291,7 +291,7 @@ class PinterestSearchExtractor(PinterestExtractor):
     """Extractor for Pinterest search results"""
     subcategory = "search"
     directory_fmt = ("{category}", "Search", "{search}")
-    pattern = rf"{BASE_PATTERN}/search/pins/?\?q=([^&#]+)"
+    pattern = BASE_PATTERN + r"/search/pins/?\?q=([^&#]+)"
     example = "https://www.pinterest.com/search/pins/?q=QUERY"
 
     def __init__(self, match):
@@ -308,7 +308,7 @@ class PinterestSearchExtractor(PinterestExtractor):
 class PinterestPinExtractor(PinterestExtractor):
     """Extractor for images from a single pin from pinterest.com"""
     subcategory = "pin"
-    pattern = rf"{BASE_PATTERN}/pin/([^/?#]+)(?!.*#related$)"
+    pattern = BASE_PATTERN + r"/pin/([^/?#]+)(?!.*#related$)"
     example = "https://www.pinterest.com/pin/12345/"
 
     def __init__(self, match):
@@ -329,7 +329,7 @@ class PinterestBoardExtractor(PinterestExtractor):
     subcategory = "board"
     directory_fmt = ("{category}", "{board[owner][username]}", "{board[name]}")
     archive_fmt = "{board[id]}_{id}"
-    pattern = (rf"{BASE_PATTERN}/(?!pin/)([^/?#]+)"
+    pattern = (BASE_PATTERN + r"/(?!pin/)([^/?#]+)"
                r"/([^/?#]+)/?(?!.*#related$)")
     example = "https://www.pinterest.com/USER/BOARD/"
 
@@ -361,7 +361,7 @@ class PinterestRelatedPinExtractor(PinterestPinExtractor):
     """Extractor for related pins of another pin from pinterest.com"""
     subcategory = "related-pin"
     directory_fmt = ("{category}", "related {original_pin[id]}")
-    pattern = rf"{BASE_PATTERN}/pin/([^/?#]+).*#related$"
+    pattern = BASE_PATTERN + r"/pin/([^/?#]+).*#related$"
     example = "https://www.pinterest.com/pin/12345/#related"
 
     def metadata(self):
@@ -376,7 +376,7 @@ class PinterestRelatedBoardExtractor(PinterestBoardExtractor):
     subcategory = "related-board"
     directory_fmt = ("{category}", "{board[owner][username]}",
                      "{board[name]}", "related")
-    pattern = rf"{BASE_PATTERN}/(?!pin/)([^/?#]+)/([^/?#]+)/?#related$"
+    pattern = BASE_PATTERN + r"/(?!pin/)([^/?#]+)/([^/?#]+)/?#related$"
     example = "https://www.pinterest.com/USER/BOARD/#related"
 
     def pins(self):
diff --git a/gallery_dl/extractor/pixeldrain.py b/gallery_dl/extractor/pixeldrain.py
index 1486976b..f299db99 100644
--- a/gallery_dl/extractor/pixeldrain.py
+++ b/gallery_dl/extractor/pixeldrain.py
@@ -29,7 +29,7 @@ class PixeldrainFileExtractor(PixeldrainExtractor):
     """Extractor for pixeldrain files"""
     subcategory = "file"
     filename_fmt = "{filename[:230]} ({id}).{extension}"
-    pattern = rf"{BASE_PATTERN}/(?:u|api/file)/(\w+)"
+    pattern = BASE_PATTERN + r"/(?:u|api/file)/(\w+)"
     example = "https://pixeldrain.com/u/abcdefgh"
 
     def __init__(self, match):
@@ -54,7 +54,7 @@ class PixeldrainAlbumExtractor(PixeldrainExtractor):
     directory_fmt = ("{category}",
                      "{album[date]:%Y-%m-%d} {album[title]} ({album[id]})")
     filename_fmt = "{num:>03} {filename[:230]} ({id}).{extension}"
-    pattern = rf"{BASE_PATTERN}/(?:l|api/list)/(\w+)(?:#item=(\d+))?"
+    pattern = BASE_PATTERN + r"/(?:l|api/list)/(\w+)(?:#item=(\d+))?"
     example = "https://pixeldrain.com/l/abcdefgh"
 
     def __init__(self, match):
@@ -97,7 +97,7 @@ class PixeldrainFolderExtractor(PixeldrainExtractor):
     subcategory = "folder"
     filename_fmt = "{filename[:230]}.{extension}"
     archive_fmt = "{path}_{num}"
-    pattern = rf"{BASE_PATTERN}/(?:d|api/filesystem)/([^?]+)"
+    pattern = BASE_PATTERN + r"/(?:d|api/filesystem)/([^?]+)"
     example = "https://pixeldrain.com/d/abcdefgh"
 
     def metadata(self, data):
diff --git a/gallery_dl/extractor/pixiv.py b/gallery_dl/extractor/pixiv.py
index eb1a7f29..d51f8c79 100644
--- a/gallery_dl/extractor/pixiv.py
+++ b/gallery_dl/extractor/pixiv.py
@@ -15,7 +15,7 @@ import itertools
 import hashlib
 
 BASE_PATTERN = r"(?:https?://)?(?:www\.|touch\.)?ph?ixiv\.net"
-USER_PATTERN = rf"{BASE_PATTERN}/(?:en/)?users/(\d+)"
+USER_PATTERN = BASE_PATTERN + r"/(?:en/)?users/(\d+)"
 
 
 class PixivExtractor(Extractor):
@@ -393,7 +393,7 @@ class PixivExtractor(Extractor):
 
 class PixivUserExtractor(Dispatch, PixivExtractor):
     """Extractor for a pixiv user profile"""
-    pattern = (rf"{BASE_PATTERN}/(?:"
+    pattern = (BASE_PATTERN + r"/(?:"
                r"(?:en/)?u(?:sers)?/|member\.php\?id=|(?:mypage\.php)?#id="
                r")(\d+)(?:$|[?#])")
     example = "https://www.pixiv.net/en/users/12345"
@@ -416,7 +416,7 @@ class PixivUserExtractor(Dispatch, PixivExtractor):
 class PixivArtworksExtractor(PixivExtractor):
     """Extractor for artworks of a pixiv user"""
     subcategory = "artworks"
-    pattern = (rf"{BASE_PATTERN}/(?:"
+    pattern = (BASE_PATTERN + r"/(?:"
                r"(?:en/)?users/(\d+)/(?:artworks|illustrations|manga)"
                r"(?:/([^/?#]+))?/?(?:$|[?#])"
                r"|member_illust\.php\?id=(\d+)(?:&([^#]+))?)")
@@ -505,7 +505,7 @@ class PixivAvatarExtractor(PixivExtractor):
     subcategory = "avatar"
     filename_fmt = "avatar{date:?_//%Y-%m-%d}.{extension}"
     archive_fmt = "avatar_{user[id]}_{date}"
-    pattern = rf"{USER_PATTERN}/avatar"
+    pattern = USER_PATTERN + r"/avatar"
     example = "https://www.pixiv.net/en/users/12345/avatar"
 
     def _init(self):
@@ -523,7 +523,7 @@ class PixivBackgroundExtractor(PixivExtractor):
     subcategory = "background"
     filename_fmt = "background{date:?_//%Y-%m-%d}.{extension}"
     archive_fmt = "background_{user[id]}_{date}"
-    pattern = rf"{USER_PATTERN}/background"
+    pattern = USER_PATTERN + "/background"
     example = "https://www.pixiv.net/en/users/12345/background"
 
     def _init(self):
@@ -585,7 +585,7 @@ class PixivWorkExtractor(PixivExtractor):
 class PixivUnlistedExtractor(PixivExtractor):
     """Extractor for a unlisted pixiv illustrations"""
     subcategory = "unlisted"
-    pattern = rf"{BASE_PATTERN}/(?:en/)?artworks/unlisted/(\w+)"
+    pattern = BASE_PATTERN + r"/(?:en/)?artworks/unlisted/(\w+)"
     example = "https://www.pixiv.net/en/artworks/unlisted/a1b2c3d4e5f6g7h8i9j0"
 
     def _extract_files(self, work):
@@ -604,7 +604,7 @@ class PixivFavoriteExtractor(PixivExtractor):
     directory_fmt = ("{category}", "bookmarks",
                      "{user_bookmark[id]} {user_bookmark[account]}")
     archive_fmt = "f_{user_bookmark[id]}_{id}{num}.{extension}"
-    pattern = (rf"{BASE_PATTERN}/(?:(?:en/)?"
+    pattern = (BASE_PATTERN + r"/(?:(?:en/)?"
                r"users/(\d+)/(bookmarks/artworks|following)(?:/([^/?#]+))?"
                r"|bookmark\.php)(?:\?([^#]*))?")
     example = "https://www.pixiv.net/en/users/12345/bookmarks/artworks"
@@ -657,7 +657,7 @@ class PixivFavoriteExtractor(PixivExtractor):
         for preview in self.api.user_following(self.user_id, restrict):
             user = preview["user"]
             user["_extractor"] = PixivUserExtractor
-            url = f"https://www.pixiv.net/users/{user['id']}"
+            url = "https://www.pixiv.net/users/" + str(user["id"])
             yield Message.Queue, url, user
 
 
@@ -667,7 +667,7 @@ class PixivRankingExtractor(PixivExtractor):
     archive_fmt = "r_{ranking[mode]}_{ranking[date]}_{id}{num}.{extension}"
     directory_fmt = ("{category}", "rankings",
                      "{ranking[mode]}", "{ranking[date]}")
-    pattern = rf"{BASE_PATTERN}/ranking\.php(?:\?([^#]*))?"
+    pattern = BASE_PATTERN + r"/ranking\.php(?:\?([^#]*))?"
     example = "https://www.pixiv.net/ranking.php"
 
     def __init__(self, match):
@@ -736,7 +736,7 @@ class PixivSearchExtractor(PixivExtractor):
     subcategory = "search"
     archive_fmt = "s_{search[word]}_{id}{num}.{extension}"
     directory_fmt = ("{category}", "search", "{search[word]}")
-    pattern = (rf"{BASE_PATTERN}/(?:(?:en/)?tags/([^/?#]+)(?:/[^/?#]+)?/?"
+    pattern = (BASE_PATTERN + r"/(?:(?:en/)?tags/([^/?#]+)(?:/[^/?#]+)?/?"
                r"|search\.php)(?:\?([^#]+))?")
     example = "https://www.pixiv.net/en/tags/TAG"
 
@@ -802,7 +802,7 @@ class PixivFollowExtractor(PixivExtractor):
     subcategory = "follow"
     archive_fmt = "F_{user_follow[id]}_{id}{num}.{extension}"
     directory_fmt = ("{category}", "following")
-    pattern = rf"{BASE_PATTERN}/bookmark_new_illust\.php"
+    pattern = BASE_PATTERN + r"/bookmark_new_illust\.php"
     example = "https://www.pixiv.net/bookmark_new_illust.php"
 
     def works(self):
@@ -851,7 +851,7 @@ class PixivSeriesExtractor(PixivExtractor):
     directory_fmt = ("{category}", "{user[id]} {user[account]}",
                      "{series[id]} {series[title]}")
     filename_fmt = "{num_series:>03}_{id}_p{num}.{extension}"
-    pattern = rf"{BASE_PATTERN}/user/(\d+)/series/(\d+)"
+    pattern = BASE_PATTERN + r"/user/(\d+)/series/(\d+)"
     example = "https://www.pixiv.net/user/12345/series/12345"
 
     def __init__(self, match):
@@ -1042,7 +1042,7 @@ class PixivNovelExtractor(PixivExtractor):
 class PixivNovelNovelExtractor(PixivNovelExtractor):
     """Extractor for pixiv novels"""
     subcategory = "novel"
-    pattern = rf"{BASE_PATTERN}/n(?:ovel/show\.php\?id=|/)(\d+)"
+    pattern = BASE_PATTERN + r"/n(?:ovel/show\.php\?id=|/)(\d+)"
     example = "https://www.pixiv.net/novel/show.php?id=12345"
 
     def novels(self):
@@ -1056,7 +1056,7 @@ class PixivNovelNovelExtractor(PixivNovelExtractor):
 class PixivNovelUserExtractor(PixivNovelExtractor):
     """Extractor for pixiv users' novels"""
     subcategory = "user"
-    pattern = rf"{USER_PATTERN}/novels"
+    pattern = USER_PATTERN + r"/novels"
     example = "https://www.pixiv.net/en/users/12345/novels"
 
     def novels(self):
@@ -1066,7 +1066,7 @@ class PixivNovelUserExtractor(PixivNovelExtractor):
 class PixivNovelSeriesExtractor(PixivNovelExtractor):
     """Extractor for pixiv novel series"""
     subcategory = "series"
-    pattern = rf"{BASE_PATTERN}/novel/series/(\d+)"
+    pattern = BASE_PATTERN + r"/novel/series/(\d+)"
     example = "https://www.pixiv.net/novel/series/12345"
 
     def novels(self):
@@ -1076,7 +1076,7 @@ class PixivNovelSeriesExtractor(PixivNovelExtractor):
 class PixivNovelBookmarkExtractor(PixivNovelExtractor):
     """Extractor for bookmarked pixiv novels"""
     subcategory = "bookmark"
-    pattern = (rf"{USER_PATTERN}/bookmarks/novels"
+    pattern = (USER_PATTERN + r"/bookmarks/novels"
                r"(?:/([^/?#]+))?(?:/?\?([^#]+))?")
     example = "https://www.pixiv.net/en/users/12345/bookmarks/novels"
 
@@ -1302,7 +1302,7 @@ class PixivAppAPI():
             msg = (f"'{msg}'" if (msg := error.get("user_message")) else
                    f"'{msg}'" if (msg := error.get("message")) else
                    error)
-            raise exception.AbortExtraction(f"API request failed: {msg}")
+            raise exception.AbortExtraction("API request failed: " + msg)
 
     def _pagination(self, endpoint, params,
                     key_items="illusts", key_data=None, key_user=None):
diff --git a/gallery_dl/extractor/pixnet.py b/gallery_dl/extractor/pixnet.py
index 2feab954..68f546ba 100644
--- a/gallery_dl/extractor/pixnet.py
+++ b/gallery_dl/extractor/pixnet.py
@@ -65,7 +65,7 @@ class PixnetImageExtractor(PixnetExtractor):
     subcategory = "image"
     filename_fmt = "{id}.{extension}"
     directory_fmt = ("{category}", "{blog}")
-    pattern = rf"{BASE_PATTERN}/album/photo/(\d+)"
+    pattern = BASE_PATTERN + r"/album/photo/(\d+)"
     example = "https://USER.pixnet.net/album/photo/12345"
 
     def items(self):
@@ -92,7 +92,7 @@ class PixnetSetExtractor(PixnetExtractor):
     subcategory = "set"
     directory_fmt = ("{category}", "{blog}",
                      "{folder_id} {folder_title}", "{set_id} {set_title}")
-    pattern = rf"{BASE_PATTERN}/album/set/(\d+)"
+    pattern = BASE_PATTERN + r"/album/set/(\d+)"
     example = "https://USER.pixnet.net/album/set/12345"
 
     def items(self):
@@ -137,7 +137,7 @@ class PixnetFolderExtractor(PixnetExtractor):
     """Extractor for all sets in a pixnet folder"""
     subcategory = "folder"
     url_fmt = "{}/album/folder/{}"
-    pattern = rf"{BASE_PATTERN}/album/folder/(\d+)"
+    pattern = BASE_PATTERN + r"/album/folder/(\d+)"
     example = "https://USER.pixnet.net/album/folder/12345"
 
 
@@ -145,5 +145,5 @@ class PixnetUserExtractor(PixnetExtractor):
     """Extractor for all sets and folders of a pixnet user"""
     subcategory = "user"
     url_fmt = "{}{}/album/list"
-    pattern = rf"{BASE_PATTERN}()(?:/blog|/album(?:/list)?)?/?(?:$|[?#])"
+    pattern = BASE_PATTERN + r"()(?:/blog|/album(?:/list)?)?/?(?:$|[?#])"
     example = "https://USER.pixnet.net/"
diff --git a/gallery_dl/extractor/poipiku.py b/gallery_dl/extractor/poipiku.py
index c3aaabad..23f3b54e 100644
--- a/gallery_dl/extractor/poipiku.py
+++ b/gallery_dl/extractor/poipiku.py
@@ -54,7 +54,7 @@ class PoipikuExtractor(Extractor):
 
         for post_url in self.posts():
             if post_url[0] == "/":
-                post_url = f"{self.root}{post_url}"
+                post_url = self.root + post_url
             page = self.request(post_url).text
             extr = text.extract_from(page)
             parts = post_url.rsplit("/", 2)
@@ -148,7 +148,7 @@ class PoipikuExtractor(Extractor):
         return files
 
     def _show_illust_detail(self, post):
-        url = f"{self.root}/f/ShowIllustDetailF.jsp"
+        url = self.root + "/f/ShowIllustDetailF.jsp"
         data = {
             "ID" : post["user_id"],
             "TD" : post["post_id"],
@@ -160,7 +160,7 @@ class PoipikuExtractor(Extractor):
             interval=False)
 
     def _show_append_file(self, post):
-        url = f"{self.root}/f/ShowAppendFileF.jsp"
+        url = self.root + "/f/ShowAppendFileF.jsp"
         data = {
             "UID": post["user_id"],
             "IID": post["post_id"],
@@ -176,14 +176,14 @@ class PoipikuExtractor(Extractor):
 class PoipikuUserExtractor(PoipikuExtractor):
     """Extractor for posts from a poipiku user"""
     subcategory = "user"
-    pattern = (rf"{BASE_PATTERN}/(?:IllustListPcV\.jsp\?PG=(\d+)&ID=)?"
-               rf"(\d+)/?(?:$|[?&#])")
+    pattern = (BASE_PATTERN + r"/(?:IllustListPcV\.jsp\?PG=(\d+)&ID=)?"
+               r"(\d+)/?(?:$|[?&#])")
     example = "https://poipiku.com/12345/"
 
     def posts(self):
         pnum, user_id = self.groups
 
-        url = f"{self.root}/IllustListPcV.jsp"
+        url = self.root + "/IllustListPcV.jsp"
         params = {
             "PG" : text.parse_int(pnum, 0),
             "ID" : user_id,
@@ -207,7 +207,7 @@ class PoipikuUserExtractor(PoipikuExtractor):
 class PoipikuPostExtractor(PoipikuExtractor):
     """Extractor for a poipiku post"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/(\d+)/(\d+)"
+    pattern = BASE_PATTERN + r"/(\d+)/(\d+)"
     example = "https://poipiku.com/12345/12345.html"
 
     def posts(self):
diff --git a/gallery_dl/extractor/poringa.py b/gallery_dl/extractor/poringa.py
index 832bedf3..94a493f2 100644
--- a/gallery_dl/extractor/poringa.py
+++ b/gallery_dl/extractor/poringa.py
@@ -104,7 +104,7 @@ class PoringaExtractor(Extractor):
 class PoringaPostExtractor(PoringaExtractor):
     """Extractor for posts on poringa.net"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/posts/imagenes/(\d+)"
+    pattern = BASE_PATTERN + r"/posts/imagenes/(\d+)"
     example = "http://www.poringa.net/posts/imagenes/12345/TITLE.html"
 
     def posts(self):
@@ -113,7 +113,7 @@ class PoringaPostExtractor(PoringaExtractor):
 
 class PoringaUserExtractor(PoringaExtractor):
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/(\w+)$"
+    pattern = BASE_PATTERN + r"/(\w+)$"
     example = "http://www.poringa.net/USER"
 
     def posts(self):
@@ -124,7 +124,7 @@ class PoringaUserExtractor(PoringaExtractor):
 
 class PoringaSearchExtractor(PoringaExtractor):
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/buscar/\?&?q=([^&#]+)"
+    pattern = BASE_PATTERN + r"/buscar/\?&?q=([^&#]+)"
     example = "http://www.poringa.net/buscar/?q=QUERY"
 
     def posts(self):
diff --git a/gallery_dl/extractor/pornhub.py b/gallery_dl/extractor/pornhub.py
index 5ced3150..d4ee3bc0 100644
--- a/gallery_dl/extractor/pornhub.py
+++ b/gallery_dl/extractor/pornhub.py
@@ -54,7 +54,7 @@ class PornhubGalleryExtractor(PornhubExtractor):
     directory_fmt = ("{category}", "{user}", "{gallery[id]} {gallery[title]}")
     filename_fmt = "{num:>03}_{id}.{extension}"
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}/album/(\d+)"
+    pattern = BASE_PATTERN + r"/album/(\d+)"
     example = "https://www.pornhub.com/album/12345"
 
     def __init__(self, match):
@@ -134,7 +134,7 @@ class PornhubGifExtractor(PornhubExtractor):
     directory_fmt = ("{category}", "{user}", "gifs")
     filename_fmt = "{id} {title}.{extension}"
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}/gif/(\d+)"
+    pattern = BASE_PATTERN + r"/gif/(\d+)"
     example = "https://www.pornhub.com/gif/12345"
 
     def __init__(self, match):
@@ -163,7 +163,7 @@ class PornhubGifExtractor(PornhubExtractor):
 
 class PornhubUserExtractor(Dispatch, PornhubExtractor):
     """Extractor for a pornhub user"""
-    pattern = rf"{BASE_PATTERN}/((?:users|model|pornstar)/[^/?#]+)/?$"
+    pattern = BASE_PATTERN + r"/((?:users|model|pornstar)/[^/?#]+)/?$"
     example = "https://www.pornhub.com/model/USER"
 
     def items(self):
@@ -177,7 +177,7 @@ class PornhubUserExtractor(Dispatch, PornhubExtractor):
 class PornhubPhotosExtractor(PornhubExtractor):
     """Extractor for all galleries of a pornhub user"""
     subcategory = "photos"
-    pattern = (rf"{BASE_PATTERN}/((?:users|model|pornstar)/[^/?#]+)"
+    pattern = (BASE_PATTERN + r"/((?:users|model|pornstar)/[^/?#]+)"
                "/(photos(?:/[^/?#]+)?)")
     example = "https://www.pornhub.com/model/USER/photos"
 
@@ -198,7 +198,7 @@ class PornhubPhotosExtractor(PornhubExtractor):
 class PornhubGifsExtractor(PornhubExtractor):
     """Extractor for a pornhub user's gifs"""
     subcategory = "gifs"
-    pattern = (rf"{BASE_PATTERN}/((?:users|model|pornstar)/[^/?#]+)"
+    pattern = (BASE_PATTERN + r"/((?:users|model|pornstar)/[^/?#]+)"
                "/(gifs(?:/[^/?#]+)?)")
     example = "https://www.pornhub.com/model/USER/gifs"
 
diff --git a/gallery_dl/extractor/pornpics.py b/gallery_dl/extractor/pornpics.py
index 9c926e8c..0bcd7f4a 100644
--- a/gallery_dl/extractor/pornpics.py
+++ b/gallery_dl/extractor/pornpics.py
@@ -58,7 +58,7 @@ class PornpicsExtractor(Extractor):
 
 class PornpicsGalleryExtractor(PornpicsExtractor, GalleryExtractor):
     """Extractor for pornpics galleries"""
-    pattern = rf"{BASE_PATTERN}/galleries/((?:[^/?#]+-)?(\d+))"
+    pattern = BASE_PATTERN + r"/galleries/((?:[^/?#]+-)?(\d+))"
     example = "https://www.pornpics.com/galleries/TITLE-12345/"
 
     def __init__(self, match):
@@ -94,7 +94,7 @@ class PornpicsGalleryExtractor(PornpicsExtractor, GalleryExtractor):
 class PornpicsTagExtractor(PornpicsExtractor):
     """Extractor for galleries from pornpics tag searches"""
     subcategory = "tag"
-    pattern = rf"{BASE_PATTERN}/tags/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/tags/([^/?#]+)"
     example = "https://www.pornpics.com/tags/TAGS/"
 
     def galleries(self):
@@ -105,7 +105,7 @@ class PornpicsTagExtractor(PornpicsExtractor):
 class PornpicsSearchExtractor(PornpicsExtractor):
     """Extractor for galleries from pornpics search results"""
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/(?:\?q=|pornstars/|channels/)([^/&#]+)"
+    pattern = BASE_PATTERN + r"/(?:\?q=|pornstars/|channels/)([^/&#]+)"
     example = "https://www.pornpics.com/?q=QUERY"
 
     def galleries(self):
@@ -125,8 +125,8 @@ class PornpicsListingExtractor(PornpicsExtractor):
     and use single quotes in HTML, unlike category pages.
     """
     subcategory = "listing"
-    pattern = (rf"{BASE_PATTERN}"
-               rf"/(popular|recent|rating|likes|views|comments)/?$")
+    pattern = (BASE_PATTERN +
+               r"/(popular|recent|rating|likes|views|comments)/?$")
     example = "https://www.pornpics.com/popular/"
 
     def galleries(self):
@@ -142,7 +142,7 @@ class PornpicsListingExtractor(PornpicsExtractor):
 class PornpicsCategoryExtractor(PornpicsExtractor):
     """Extractor for galleries from pornpics categories"""
     subcategory = "category"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/?$"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/?$"
     example = "https://www.pornpics.com/ass/"
 
     def galleries(self):
diff --git a/gallery_dl/extractor/postmill.py b/gallery_dl/extractor/postmill.py
index e71246aa..22d2bded 100644
--- a/gallery_dl/extractor/postmill.py
+++ b/gallery_dl/extractor/postmill.py
@@ -95,7 +95,7 @@ class PostmillSubmissionsExtractor(PostmillExtractor):
             groups[-1]).items() if self.acceptable_query(key)}
 
     def items(self):
-        url = self.root + self.base + self.sorting_path
+        url = f"{self.root}{self.base}{self.sorting_path}"
 
         while url:
             response = self.request(url, params=self.query)
@@ -130,14 +130,14 @@ BASE_PATTERN = PostmillExtractor.update({
     }
 })
 QUERY_RE = r"(?:\?([^#]+))?$"
-SORTING_RE = (rf"(/(?:hot|new|active|top|controversial|most_commented))?"
-              rf"{QUERY_RE}")
+SORTING_RE = (r"(/(?:hot|new|active|top|controversial|most_commented))?" +
+              QUERY_RE)
 
 
 class PostmillPostExtractor(PostmillExtractor):
     """Extractor for a single submission URL"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/f/(\w+)/(\d+)"
+    pattern = BASE_PATTERN + r"/f/(\w+)/(\d+)"
     example = "https://raddle.me/f/FORUM/123/TITLE"
 
     def __init__(self, match):
@@ -146,13 +146,13 @@ class PostmillPostExtractor(PostmillExtractor):
         self.post_id = match[4]
 
     def post_urls(self):
-        return (self.root + "/f/" + self.forum + "/" + self.post_id,)
+        return (f"{self.root}/f/{self.forum}/{self.post_id}",)
 
 
 class PostmillShortURLExtractor(PostmillExtractor):
     """Extractor for short submission URLs"""
     subcategory = "shorturl"
-    pattern = rf"{BASE_PATTERN}(/\d+)$"
+    pattern = BASE_PATTERN + r"(/\d+)$"
     example = "https://raddle.me/123"
 
     def items(self):
@@ -193,6 +193,6 @@ class PostmillTagExtractor(PostmillSubmissionsExtractor):
 class PostmillSearchExtractor(PostmillSubmissionsExtractor):
     """Extractor for search results"""
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}(/search)()\?(q=[^#]+)$"
+    pattern = BASE_PATTERN + r"(/search)()\?(q=[^#]+)$"
     example = "https://raddle.me/search?q=QUERY"
     whitelisted_parameters = ("q",)
diff --git a/gallery_dl/extractor/rawkuma.py b/gallery_dl/extractor/rawkuma.py
index a4a0c9b2..4a115493 100644
--- a/gallery_dl/extractor/rawkuma.py
+++ b/gallery_dl/extractor/rawkuma.py
@@ -21,7 +21,7 @@ class RawkumaBase():
 class RawkumaChapterExtractor(RawkumaBase, ChapterExtractor):
     """Extractor for manga chapters from rawkuma.net"""
     archive_fmt = "{chapter_id}_{page}"
-    pattern = rf"{BASE_PATTERN}(/manga/[^/?#]+/chapter-\d+(?:.\d+)?\.(\d+))"
+    pattern = BASE_PATTERN + r"(/manga/[^/?#]+/chapter-\d+(?:.\d+)?\.(\d+))"
     example = "https://rawkuma.net/manga/7TITLE/chapter-123.321"
 
     def __init__(self, match):
@@ -54,7 +54,7 @@ class RawkumaChapterExtractor(RawkumaBase, ChapterExtractor):
 class RawkumaMangaExtractor(RawkumaBase, MangaExtractor):
     """Extractor for manga from rawkuma.net"""
     chapterclass = RawkumaChapterExtractor
-    pattern = rf"{BASE_PATTERN}/manga/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/manga/([^/?#]+)"
     example = "https://rawkuma.net/manga/TITLE/"
 
     def __init__(self, match):
@@ -65,7 +65,7 @@ class RawkumaMangaExtractor(RawkumaBase, MangaExtractor):
         manga = text.unescape(text.extr(page, "<title>", " &#8211; "))
         manga_id = text.parse_int(text.extr(page, "manga_id=", "&"))
 
-        url = f"{self.root}/wp-admin/admin-ajax.php"
+        url = self.root + "/wp-admin/admin-ajax.php"
         params = {
             "manga_id": manga_id,
             "page"    : "1",
diff --git a/gallery_dl/extractor/reactor.py b/gallery_dl/extractor/reactor.py
index 8e974d21..8fd29d28 100644
--- a/gallery_dl/extractor/reactor.py
+++ b/gallery_dl/extractor/reactor.py
@@ -171,7 +171,7 @@ class ReactorTagExtractor(ReactorExtractor):
     subcategory = "tag"
     directory_fmt = ("{category}", "{search_tags}")
     archive_fmt = "{search_tags}_{post_id}_{num}"
-    pattern = rf"{BASE_PATTERN}/tag/([^/?#]+)(?:/[^/?#]+)?"
+    pattern = BASE_PATTERN + r"/tag/([^/?#]+)(?:/[^/?#]+)?"
     example = "http://reactor.cc/tag/TAG"
 
     def __init__(self, match):
@@ -187,7 +187,7 @@ class ReactorSearchExtractor(ReactorExtractor):
     subcategory = "search"
     directory_fmt = ("{category}", "search", "{search_tags}")
     archive_fmt = "s_{search_tags}_{post_id}_{num}"
-    pattern = rf"{BASE_PATTERN}/search(?:/|\?q=)([^/?#]+)"
+    pattern = BASE_PATTERN + r"/search(?:/|\?q=)([^/?#]+)"
     example = "http://reactor.cc/search?q=QUERY"
 
     def __init__(self, match):
@@ -202,7 +202,7 @@ class ReactorUserExtractor(ReactorExtractor):
     """Extractor for all posts of a user on *reactor.cc sites"""
     subcategory = "user"
     directory_fmt = ("{category}", "user", "{user}")
-    pattern = rf"{BASE_PATTERN}/user/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/user/([^/?#]+)"
     example = "http://reactor.cc/user/USER"
 
     def __init__(self, match):
@@ -216,7 +216,7 @@ class ReactorUserExtractor(ReactorExtractor):
 class ReactorPostExtractor(ReactorExtractor):
     """Extractor for single posts on *reactor.cc sites"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/post/(\d+)"
+    pattern = BASE_PATTERN + r"/post/(\d+)"
     example = "http://reactor.cc/post/12345"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/readcomiconline.py b/gallery_dl/extractor/readcomiconline.py
index dccf91d4..24a01712 100644
--- a/gallery_dl/extractor/readcomiconline.py
+++ b/gallery_dl/extractor/readcomiconline.py
@@ -44,7 +44,7 @@ class ReadcomiconlineBase():
 class ReadcomiconlineIssueExtractor(ReadcomiconlineBase, ChapterExtractor):
     """Extractor for comic-issues from readcomiconline.li"""
     subcategory = "issue"
-    pattern = rf"{BASE_PATTERN}(/Comic/[^/?#]+/[^/?#]+\?)([^#]+)"
+    pattern = BASE_PATTERN + r"(/Comic/[^/?#]+/[^/?#]+\?)([^#]+)"
     example = "https://readcomiconline.li/Comic/TITLE/Issue-123?id=12345"
 
     def _init(self):
@@ -98,7 +98,7 @@ class ReadcomiconlineComicExtractor(ReadcomiconlineBase, MangaExtractor):
     """Extractor for comics from readcomiconline.li"""
     chapterclass = ReadcomiconlineIssueExtractor
     subcategory = "comic"
-    pattern = rf"{BASE_PATTERN}(/Comic/[^/?#]+/?)$"
+    pattern = BASE_PATTERN + r"(/Comic/[^/?#]+/?)$"
     example = "https://readcomiconline.li/Comic/TITLE"
 
     def chapters(self, page):
diff --git a/gallery_dl/extractor/realbooru.py b/gallery_dl/extractor/realbooru.py
index 7f731f81..3454340c 100644
--- a/gallery_dl/extractor/realbooru.py
+++ b/gallery_dl/extractor/realbooru.py
@@ -49,7 +49,7 @@ class RealbooruExtractor(booru.BooruExtractor):
             tags.append(tag)
             tags_categories[tag_type].append(tag)
         for key, value in tags_categories.items():
-            post[f"tags_{key}"] = ", ".join(value)
+            post["tags_" + key] = ", ".join(value)
         tags.sort()
 
         post["tags"] = ", ".join(tags)
@@ -85,7 +85,7 @@ class RealbooruTagExtractor(RealbooruExtractor):
     directory_fmt = ("{category}", "{search_tags}")
     archive_fmt = "t_{search_tags}_{id}"
     per_page = 42
-    pattern = rf"{BASE_PATTERN}/index\.php\?page=post&s=list&tags=([^&#]*)"
+    pattern = BASE_PATTERN + r"/index\.php\?page=post&s=list&tags=([^&#]*)"
     example = "https://realbooru.com/index.php?page=post&s=list&tags=TAG"
 
     def metadata(self):
@@ -105,7 +105,7 @@ class RealbooruFavoriteExtractor(RealbooruExtractor):
     directory_fmt = ("{category}", "favorites", "{favorite_id}")
     archive_fmt = "f_{favorite_id}_{id}"
     per_page = 50
-    pattern = rf"{BASE_PATTERN}/index\.php\?page=favorites&s=view&id=(\d+)"
+    pattern = BASE_PATTERN + r"/index\.php\?page=favorites&s=view&id=(\d+)"
     example = "https://realbooru.com/index.php?page=favorites&s=view&id=12345"
 
     def metadata(self):
@@ -123,7 +123,7 @@ class RealbooruPoolExtractor(RealbooruExtractor):
     subcategory = "pool"
     directory_fmt = ("{category}", "pool", "{pool} {pool_name}")
     archive_fmt = "p_{pool}_{id}"
-    pattern = rf"{BASE_PATTERN}/index\.php\?page=pool&s=show&id=(\d+)"
+    pattern = BASE_PATTERN + r"/index\.php\?page=pool&s=show&id=(\d+)"
     example = "https://realbooru.com/index.php?page=pool&s=show&id=12345"
 
     def metadata(self):
@@ -150,7 +150,7 @@ class RealbooruPoolExtractor(RealbooruExtractor):
 class RealbooruPostExtractor(RealbooruExtractor):
     subcategory = "post"
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}/index\.php\?page=post&s=view&id=(\d+)"
+    pattern = BASE_PATTERN + r"/index\.php\?page=post&s=view&id=(\d+)"
     example = "https://realbooru.com/index.php?page=post&s=view&id=12345"
 
     def posts(self):
diff --git a/gallery_dl/extractor/reddit.py b/gallery_dl/extractor/reddit.py
index cc73e474..a8bde87d 100644
--- a/gallery_dl/extractor/reddit.py
+++ b/gallery_dl/extractor/reddit.py
@@ -223,10 +223,10 @@ class RedditExtractor(Extractor):
                     self.log.debug(src)
             elif url := data.get("dashUrl"):
                 submission["_ytdl_manifest"] = "dash"
-                yield f"ytdl:{url}"
+                yield "ytdl:" + url
             elif url := data.get("hlsUrl"):
                 submission["_ytdl_manifest"] = "hls"
-                yield f"ytdl:{url}"
+                yield "ytdl:" + url
 
     def _extract_video_ytdl(self, submission):
         return "https://www.reddit.com" + submission["permalink"]
@@ -506,7 +506,7 @@ class RedditAPI():
         return "Bearer " + data["access_token"]
 
     def _call(self, endpoint, params):
-        url = f"{self.root}{endpoint}"
+        url = self.root + endpoint
         params["raw_json"] = "1"
 
         while True:
diff --git a/gallery_dl/extractor/redgifs.py b/gallery_dl/extractor/redgifs.py
index 164fdf49..de8b82e6 100644
--- a/gallery_dl/extractor/redgifs.py
+++ b/gallery_dl/extractor/redgifs.py
@@ -135,7 +135,7 @@ class RedgifsCollectionsExtractor(RedgifsExtractor):
     def items(self):
         base = f"{self.root}/users/{self.key}/collections/"
         for collection in self.api.collections(self.key):
-            url = f"{base}{collection['folderId']}"
+            url = base + collection["folderId"]
             collection["_extractor"] = RedgifsCollectionExtractor
             yield Message.Queue, url, collection
 
diff --git a/gallery_dl/extractor/rule34vault.py b/gallery_dl/extractor/rule34vault.py
index 9f75f646..74d79d3f 100644
--- a/gallery_dl/extractor/rule34vault.py
+++ b/gallery_dl/extractor/rule34vault.py
@@ -79,7 +79,7 @@ class Rule34vaultExtractor(BooruExtractor):
 class Rule34vaultPostExtractor(Rule34vaultExtractor):
     subcategory = "post"
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}/post/(\d+)"
+    pattern = BASE_PATTERN + r"/post/(\d+)"
     example = "https://rule34vault.com/post/12345"
 
     def posts(self):
@@ -90,7 +90,7 @@ class Rule34vaultPlaylistExtractor(Rule34vaultExtractor):
     subcategory = "playlist"
     directory_fmt = ("{category}", "{playlist_id}")
     archive_fmt = "p_{playlist_id}_{id}"
-    pattern = rf"{BASE_PATTERN}/playlists/view/(\d+)"
+    pattern = BASE_PATTERN + r"/playlists/view/(\d+)"
     example = "https://rule34vault.com/playlists/view/12345"
 
     def metadata(self):
@@ -105,7 +105,7 @@ class Rule34vaultTagExtractor(Rule34vaultExtractor):
     subcategory = "tag"
     directory_fmt = ("{category}", "{search_tags}")
     archive_fmt = "t_{search_tags}_{id}"
-    pattern = rf"{BASE_PATTERN}/(?!p(?:ost|laylists)/)([^/?#]+)"
+    pattern = BASE_PATTERN + r"/(?!p(?:ost|laylists)/)([^/?#]+)"
     example = "https://rule34vault.com/TAG"
 
     def metadata(self):
diff --git a/gallery_dl/extractor/rule34xyz.py b/gallery_dl/extractor/rule34xyz.py
index ddd656fc..b395f03f 100644
--- a/gallery_dl/extractor/rule34xyz.py
+++ b/gallery_dl/extractor/rule34xyz.py
@@ -120,13 +120,13 @@ class Rule34xyzExtractor(BooruExtractor):
     def _login_impl(self, username, password):
         self.log.info("Logging in as %s", username)
 
-        url = f"{self.root}/api/v2/auth/signin"
+        url = self.root + "/api/v2/auth/signin"
         data = {"email": username, "password": password}
         response = self.request_json(
             url, method="POST", json=data, fatal=False)
 
         if jwt := response.get("jwt"):
-            return f"Bearer {jwt}"
+            return "Bearer " + jwt
         raise exception.AuthenticationError(
             (msg := response.get("message")) and f'"{msg}"')
 
@@ -134,7 +134,7 @@ class Rule34xyzExtractor(BooruExtractor):
 class Rule34xyzPostExtractor(Rule34xyzExtractor):
     subcategory = "post"
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}/post/(\d+)"
+    pattern = BASE_PATTERN + r"/post/(\d+)"
     example = "https://rule34.xyz/post/12345"
 
     def posts(self):
@@ -145,7 +145,7 @@ class Rule34xyzPlaylistExtractor(Rule34xyzExtractor):
     subcategory = "playlist"
     directory_fmt = ("{category}", "{playlist_id}")
     archive_fmt = "p_{playlist_id}_{id}"
-    pattern = rf"{BASE_PATTERN}/playlists/view/(\d+)"
+    pattern = BASE_PATTERN + r"/playlists/view/(\d+)"
     example = "https://rule34.xyz/playlists/view/12345"
 
     def metadata(self):
@@ -160,7 +160,7 @@ class Rule34xyzTagExtractor(Rule34xyzExtractor):
     subcategory = "tag"
     directory_fmt = ("{category}", "{search_tags}")
     archive_fmt = "t_{search_tags}_{id}"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)$"
+    pattern = BASE_PATTERN + r"/([^/?#]+)$"
     example = "https://rule34.xyz/TAG"
 
     def metadata(self):
diff --git a/gallery_dl/extractor/s3ndpics.py b/gallery_dl/extractor/s3ndpics.py
index 9201a3f2..7eeeece9 100644
--- a/gallery_dl/extractor/s3ndpics.py
+++ b/gallery_dl/extractor/s3ndpics.py
@@ -18,7 +18,7 @@ class S3ndpicsExtractor(Extractor):
     """Base class for s3ndpics extractors"""
     category = "s3ndpics"
     root = "https://s3nd.pics"
-    root_api = f"{root}/api"
+    root_api = root + "/api"
     directory_fmt = ("{category}", "{user[username]}",
                      "{date} {title:?/ /}({id})")
     filename_fmt = "{num:>02}.{extension}"
@@ -41,7 +41,7 @@ class S3ndpicsExtractor(Extractor):
                 post["type"] = file["type"]
                 path = file["url"]
                 text.nameext_from_url(path, post)
-                yield Message.Url, f"{base}{path}", post
+                yield Message.Url, base + path, post
 
     def _pagination(self, url, params):
         params["page"] = 1
@@ -59,7 +59,7 @@ class S3ndpicsExtractor(Extractor):
 
 class S3ndpicsPostExtractor(S3ndpicsExtractor):
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/post/([0-9a-f]+)"
+    pattern = BASE_PATTERN + r"/post/([0-9a-f]+)"
     example = "https://s3nd.pics/post/0123456789abcdef01234567"
 
     def posts(self):
@@ -69,14 +69,14 @@ class S3ndpicsPostExtractor(S3ndpicsExtractor):
 
 class S3ndpicsUserExtractor(S3ndpicsExtractor):
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/user/(\w+)"
+    pattern = BASE_PATTERN + r"/user/(\w+)"
     example = "https://s3nd.pics/user/USER"
 
     def posts(self):
         url = f"{self.root_api}/users/username/{self.groups[0]}"
         self.kwdict["user"] = user = self.request_json(url)["user"]
 
-        url = f"{self.root_api}/posts"
+        url = self.root_api + "/posts"
         params = {
             "userId": user["_id"],
             "limit" : "12",
@@ -87,11 +87,11 @@ class S3ndpicsUserExtractor(S3ndpicsExtractor):
 
 class S3ndpicsSearchExtractor(S3ndpicsExtractor):
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/search/?\?([^#]+)"
+    pattern = BASE_PATTERN + r"/search/?\?([^#]+)"
     example = "https://s3nd.pics/search?QUERY"
 
     def posts(self):
-        url = f"{self.root_api}/posts"
+        url = self.root_api + "/posts"
         params = text.parse_query(self.groups[0])
         params.setdefault("limit", "20")
         self.kwdict["search_tags"] = \
diff --git a/gallery_dl/extractor/saint.py b/gallery_dl/extractor/saint.py
index e15c6282..9618b7d2 100644
--- a/gallery_dl/extractor/saint.py
+++ b/gallery_dl/extractor/saint.py
@@ -18,7 +18,7 @@ class SaintAlbumExtractor(LolisafeAlbumExtractor):
     """Extractor for saint albums"""
     category = "saint"
     root = "https://saint2.su"
-    pattern = rf"{BASE_PATTERN}/a/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/a/([^/?#]+)"
     example = "https://saint2.su/a/ID"
 
     def fetch_album(self, album_id):
@@ -58,7 +58,7 @@ class SaintMediaExtractor(SaintAlbumExtractor):
     """Extractor for saint media links"""
     subcategory = "media"
     directory_fmt = ("{category}",)
-    pattern = rf"{BASE_PATTERN}(/(embe)?d/([^/?#]+))"
+    pattern = BASE_PATTERN + r"(/(embe)?d/([^/?#]+))"
     example = "https://saint2.su/embed/ID"
 
     def fetch_album(self, album_id):
diff --git a/gallery_dl/extractor/sankaku.py b/gallery_dl/extractor/sankaku.py
index 690b515e..f8fe9106 100644
--- a/gallery_dl/extractor/sankaku.py
+++ b/gallery_dl/extractor/sankaku.py
@@ -119,7 +119,7 @@ class SankakuTagExtractor(SankakuExtractor):
     subcategory = "tag"
     directory_fmt = ("{category}", "{search_tags}")
     archive_fmt = "t_{search_tags}_{id}"
-    pattern = rf"{BASE_PATTERN}(?:/posts)?/?\?([^#]*)"
+    pattern = BASE_PATTERN + r"(?:/posts)?/?\?([^#]*)"
     example = "https://sankaku.app/?tags=TAG"
 
     def __init__(self, match):
@@ -149,7 +149,7 @@ class SankakuPoolExtractor(SankakuExtractor):
     subcategory = "pool"
     directory_fmt = ("{category}", "pool", "{pool[id]} {pool[name_en]}")
     archive_fmt = "p_{pool}_{id}"
-    pattern = rf"{BASE_PATTERN}/(?:books|pools?/show)/(\w+)"
+    pattern = BASE_PATTERN + r"/(?:books|pools?/show)/(\w+)"
     example = "https://sankaku.app/books/12345"
 
     def metadata(self):
@@ -171,7 +171,7 @@ class SankakuPostExtractor(SankakuExtractor):
     """Extractor for single posts from sankaku.app"""
     subcategory = "post"
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}/posts?(?:/show)?/(\w+)"
+    pattern = BASE_PATTERN + r"/posts?(?:/show)?/(\w+)"
     example = "https://sankaku.app/post/show/12345"
 
     def posts(self):
@@ -181,7 +181,7 @@ class SankakuPostExtractor(SankakuExtractor):
 class SankakuBooksExtractor(SankakuExtractor):
     """Extractor for books by tag search on sankaku.app"""
     subcategory = "books"
-    pattern = rf"{BASE_PATTERN}/books/?\?([^#]*)"
+    pattern = BASE_PATTERN + r"/books/?\?([^#]*)"
     example = "https://sankaku.app/books?tags=TAG"
 
     def __init__(self, match):
@@ -193,7 +193,7 @@ class SankakuBooksExtractor(SankakuExtractor):
         params = {"tags": self.tags, "pool_type": "0"}
         for pool in self.api.pools_keyset(params):
             pool["_extractor"] = SankakuPoolExtractor
-            url = f"https://sankaku.app/books/{pool['id']}"
+            url = "https://sankaku.app/books/" + pool["id"]
             yield Message.Queue, url, pool
 
 
diff --git a/gallery_dl/extractor/schalenetwork.py b/gallery_dl/extractor/schalenetwork.py
index bbbb9da4..30e57bc0 100644
--- a/gallery_dl/extractor/schalenetwork.py
+++ b/gallery_dl/extractor/schalenetwork.py
@@ -64,7 +64,7 @@ class SchalenetworkExtractor(Extractor):
 
     def _token(self, required=True):
         if token := self.config("token"):
-            return f"Bearer {token.rpartition(' ')[2]}"
+            return "Bearer " + token.rpartition(' ')[2]
         if required:
             raise exception.AuthRequired("'token'", "your favorites")
 
@@ -98,7 +98,7 @@ class SchalenetworkGalleryExtractor(SchalenetworkExtractor, GalleryExtractor):
     directory_fmt = ("{category}", "{id} {title}")
     archive_fmt = "{id}_{num}"
     request_interval = 0.0
-    pattern = rf"{BASE_PATTERN}/(?:g|reader)/(\d+)/(\w+)"
+    pattern = BASE_PATTERN + r"/(?:g|reader)/(\d+)/(\w+)"
     example = "https://niyaniya.moe/g/12345/67890abcde/"
 
     TAG_TYPES = {
@@ -172,7 +172,7 @@ class SchalenetworkGalleryExtractor(SchalenetworkExtractor, GalleryExtractor):
         if self.config("cbz", False):
             headers["Authorization"] = self._token()
             dl = self.request_json(
-                f"{url}&action=dl", method="POST", headers=headers)
+                url + "&action=dl", method="POST", headers=headers)
             # 'crt' parameter here is necessary for 'hdoujin' downloads
             url = f"{dl['base']}?crt={self._crt()}"
             info = text.nameext_from_url(url)
@@ -227,7 +227,7 @@ class SchalenetworkGalleryExtractor(SchalenetworkExtractor, GalleryExtractor):
 class SchalenetworkSearchExtractor(SchalenetworkExtractor):
     """Extractor for schale.network search results"""
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/(?:tag/([^/?#]+)|browse)?(?:/?\?([^#]*))?$"
+    pattern = BASE_PATTERN + r"/(?:tag/([^/?#]+)|browse)?(?:/?\?([^#]*))?$"
     example = "https://niyaniya.moe/browse?s=QUERY"
 
     def items(self):
@@ -252,14 +252,14 @@ class SchalenetworkSearchExtractor(SchalenetworkExtractor):
 class SchalenetworkFavoriteExtractor(SchalenetworkExtractor):
     """Extractor for schale.network favorites"""
     subcategory = "favorite"
-    pattern = rf"{BASE_PATTERN}/favorites(?:\?([^#]*))?"
+    pattern = BASE_PATTERN + r"/favorites(?:\?([^#]*))?"
     example = "https://niyaniya.moe/favorites"
 
     def items(self):
         params = text.parse_query(self.groups[1])
         params["page"] = text.parse_int(params.get("page"), 1)
         self.headers["Authorization"] = self._token()
-        return self._pagination(f"/books/favorites?crt={self._crt()}", params)
+        return self._pagination("/books/favorites?crt=" + self._crt(), params)
 
 
 SchalenetworkExtractor.extr_class = SchalenetworkGalleryExtractor
diff --git a/gallery_dl/extractor/scrolller.py b/gallery_dl/extractor/scrolller.py
index b853f533..3fce2cf6 100644
--- a/gallery_dl/extractor/scrolller.py
+++ b/gallery_dl/extractor/scrolller.py
@@ -136,7 +136,7 @@ class ScrolllerExtractor(Extractor):
 class ScrolllerSubredditExtractor(ScrolllerExtractor):
     """Extractor for media from a scrolller subreddit"""
     subcategory = "subreddit"
-    pattern = rf"{BASE_PATTERN}(/r/[^/?#]+)(?:/?\?([^#]+))?"
+    pattern = BASE_PATTERN + r"(/r/[^/?#]+)(?:/?\?([^#]+))?"
     example = "https://scrolller.com/r/SUBREDDIT"
 
     def posts(self):
@@ -173,7 +173,7 @@ class ScrolllerSubredditExtractor(ScrolllerExtractor):
 class ScrolllerFollowingExtractor(ScrolllerExtractor):
     """Extractor for followed scrolller subreddits"""
     subcategory = "following"
-    pattern = rf"{BASE_PATTERN}/following"
+    pattern = BASE_PATTERN + r"/following"
     example = "https://scrolller.com/following"
 
     def items(self):
@@ -199,7 +199,7 @@ class ScrolllerFollowingExtractor(ScrolllerExtractor):
 class ScrolllerPostExtractor(ScrolllerExtractor):
     """Extractor for media from a single scrolller post"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/(?!r/|following$)([^/?#]+)"
+    pattern = BASE_PATTERN + r"/(?!r/|following$)([^/?#]+)"
     example = "https://scrolller.com/TITLE-SLUG-a1b2c3d4f5"
 
     def posts(self):
diff --git a/gallery_dl/extractor/sexcom.py b/gallery_dl/extractor/sexcom.py
index b599f707..417538cd 100644
--- a/gallery_dl/extractor/sexcom.py
+++ b/gallery_dl/extractor/sexcom.py
@@ -194,8 +194,8 @@ class SexcomPinExtractor(SexcomExtractor):
     """Extractor for a pinned image or video on www.sex.com"""
     subcategory = "pin"
     directory_fmt = ("{category}",)
-    pattern = (rf"{BASE_PATTERN}"
-               rf"(/(?:\w\w/(?:pic|gif|video)s|pin)/\d+/?)(?!.*#related$)")
+    pattern = (BASE_PATTERN +
+               r"(/(?:\w\w/(?:pic|gif|video)s|pin)/\d+/?)(?!.*#related$)")
     example = "https://www.sex.com/pin/12345-TITLE/"
 
     def pins(self):
@@ -206,7 +206,7 @@ class SexcomRelatedPinExtractor(SexcomPinExtractor):
     """Extractor for related pins on www.sex.com"""
     subcategory = "related-pin"
     directory_fmt = ("{category}", "related {original_pin[pin_id]}")
-    pattern = rf"{BASE_PATTERN}(/pin/(\d+)/?).*#related$"
+    pattern = BASE_PATTERN + r"(/pin/(\d+)/?).*#related$"
     example = "https://www.sex.com/pin/12345#related"
 
     def metadata(self):
@@ -223,7 +223,7 @@ class SexcomPinsExtractor(SexcomExtractor):
     """Extractor for a user's pins on www.sex.com"""
     subcategory = "pins"
     directory_fmt = ("{category}", "{user}")
-    pattern = rf"{BASE_PATTERN}/user/([^/?#]+)/pins/"
+    pattern = BASE_PATTERN + r"/user/([^/?#]+)/pins/"
     example = "https://www.sex.com/user/USER/pins/"
 
     def metadata(self):
@@ -238,7 +238,7 @@ class SexcomLikesExtractor(SexcomExtractor):
     """Extractor for a user's liked pins on www.sex.com"""
     subcategory = "likes"
     directory_fmt = ("{category}", "{user}", "Likes")
-    pattern = rf"{BASE_PATTERN}/user/([^/?#]+)/likes/"
+    pattern = BASE_PATTERN + r"/user/([^/?#]+)/likes/"
     example = "https://www.sex.com/user/USER/likes/"
 
     def metadata(self):
@@ -253,8 +253,8 @@ class SexcomBoardExtractor(SexcomExtractor):
     """Extractor for pins from a board on www.sex.com"""
     subcategory = "board"
     directory_fmt = ("{category}", "{user}", "{board}")
-    pattern = (rf"{BASE_PATTERN}/user"
-               rf"/([^/?#]+)/(?!(?:following|pins|repins|likes)/)([^/?#]+)")
+    pattern = (BASE_PATTERN + r"/user"
+               r"/([^/?#]+)/(?!(?:following|pins|repins|likes)/)([^/?#]+)")
     example = "https://www.sex.com/user/USER/BOARD/"
 
     def metadata(self):
@@ -273,7 +273,7 @@ class SexcomFeedExtractor(SexcomExtractor):
     """Extractor for pins from your account's main feed on www.sex.com"""
     subcategory = "feed"
     directory_fmt = ("{category}", "feed")
-    pattern = rf"{BASE_PATTERN}/feed"
+    pattern = BASE_PATTERN + r"/feed"
     example = "https://www.sex.com/feed/"
 
     def metadata(self):
@@ -282,7 +282,7 @@ class SexcomFeedExtractor(SexcomExtractor):
     def pins(self):
         if not self.cookies_check(("sess_sex",)):
             self.log.warning("no 'sess_sex' cookie set")
-        url = f"{self.root}/feed/"
+        url = self.root + "/feed/"
         return self._pagination(url)
 
 
@@ -290,10 +290,10 @@ class SexcomSearchExtractor(SexcomExtractor):
     """Extractor for search results on www.sex.com"""
     subcategory = "search"
     directory_fmt = ("{category}", "search", "{search[search]}")
-    pattern = (rf"{BASE_PATTERN}/(?:"
-               rf"(pic|gif|video)s(?:\?(search=[^#]+)$|/([^/?#]*))"
-               rf"|search/(pic|gif|video)s"
-               rf")/?(?:\?([^#]+))?")
+    pattern = (BASE_PATTERN + r"/(?:"
+               r"(pic|gif|video)s(?:\?(search=[^#]+)$|/([^/?#]*))"
+               r"|search/(pic|gif|video)s"
+               r")/?(?:\?([^#]+))?")
     example = "https://www.sex.com/search/pics?query=QUERY"
 
     def _init(self):
@@ -341,10 +341,10 @@ class SexcomSearchExtractor(SexcomExtractor):
                     pin["type"] = "gif"
                     if gifs and pin["extension"] == "webp":
                         pin["extension"] = "gif"
-                        pin["_fallback"] = (f"{root}{path}",)
-                        path = f"{path[:-4]}gif"
+                        pin["_fallback"] = (root + path,)
+                        path = path[:-4] + "gif"
 
-                pin["url"] = f"{root}{path}"
+                pin["url"] = root + path
                 yield Message.Directory, "", pin
                 yield Message.Url, pin["url"], pin
 
diff --git a/gallery_dl/extractor/shimmie2.py b/gallery_dl/extractor/shimmie2.py
index 5572b4de..e2e1c6f3 100644
--- a/gallery_dl/extractor/shimmie2.py
+++ b/gallery_dl/extractor/shimmie2.py
@@ -100,7 +100,7 @@ class Shimmie2TagExtractor(Shimmie2Extractor):
     subcategory = "tag"
     directory_fmt = ("{category}", "{search_tags}")
     file_url_fmt = "{}/_images/{}/{}%20-%20{}.{}"
-    pattern = rf"{BASE_PATTERN}post/list/([^/?#]+)(?:/(\d+))?"
+    pattern = BASE_PATTERN + r"post/list/([^/?#]+)(?:/(\d+))?"
     example = "https://vidya.pics/post/list/TAG/1"
 
     def metadata(self):
@@ -164,7 +164,7 @@ class Shimmie2TagExtractor(Shimmie2Extractor):
 class Shimmie2PostExtractor(Shimmie2Extractor):
     """Extractor for single shimmie2 posts"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}post/view/(\d+)"
+    pattern = BASE_PATTERN + r"post/view/(\d+)"
     example = "https://vidya.pics/post/view/12345"
 
     def posts(self):
diff --git a/gallery_dl/extractor/shopify.py b/gallery_dl/extractor/shopify.py
index ad38562f..c5e5c204 100644
--- a/gallery_dl/extractor/shopify.py
+++ b/gallery_dl/extractor/shopify.py
@@ -90,7 +90,7 @@ class ShopifyCollectionExtractor(ShopifyExtractor):
     """Base class for collection extractors for Shopify based sites"""
     subcategory = "collection"
     directory_fmt = ("{category}", "{collection[title]}")
-    pattern = rf"{BASE_PATTERN}(/collections/[\w-]+)/?(?:$|[?#])"
+    pattern = BASE_PATTERN + r"(/collections/[\w-]+)/?(?:$|[?#])"
     example = "https://www.fashionnova.com/collections/TITLE"
 
     def metadata(self):
@@ -113,7 +113,7 @@ class ShopifyProductExtractor(ShopifyExtractor):
     """Base class for product extractors for Shopify based sites"""
     subcategory = "product"
     directory_fmt = ("{category}", "Products")
-    pattern = rf"{BASE_PATTERN}((?:/collections/[\w-]+)?/products/[\w-]+)"
+    pattern = BASE_PATTERN + r"((?:/collections/[\w-]+)?/products/[\w-]+)"
     example = "https://www.fashionnova.com/collections/TITLE/products/NAME"
 
     def products(self):
diff --git a/gallery_dl/extractor/sizebooru.py b/gallery_dl/extractor/sizebooru.py
index 00002b84..3b61747a 100644
--- a/gallery_dl/extractor/sizebooru.py
+++ b/gallery_dl/extractor/sizebooru.py
@@ -98,7 +98,7 @@ class SizebooruExtractor(BooruExtractor):
 class SizebooruPostExtractor(SizebooruExtractor):
     """Extractor for sizebooru posts"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/Details/(\d+)"
+    pattern = BASE_PATTERN + r"/Details/(\d+)"
     example = "https://sizebooru.com/Details/12345"
 
     def posts(self):
@@ -109,7 +109,7 @@ class SizebooruTagExtractor(SizebooruExtractor):
     """Extractor for sizebooru tag searches"""
     subcategory = "tag"
     directory_fmt = ("{category}", "{search_tags}")
-    pattern = rf"{BASE_PATTERN}/Search/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/Search/([^/?#]+)"
     example = "https://sizebooru.com/Search/TAG"
 
     def posts(self):
@@ -122,7 +122,7 @@ class SizebooruGalleryExtractor(SizebooruExtractor):
     """Extractor for sizebooru galleries"""
     subcategory = "gallery"
     directory_fmt = ("{category}", "{gallery_name} ({gallery_id})")
-    pattern = rf"{BASE_PATTERN}/Galleries/List/(\d+)"
+    pattern = BASE_PATTERN + r"/Galleries/List/(\d+)"
     example = "https://sizebooru.com/Galleries/List/123"
 
     def posts(self):
@@ -140,7 +140,7 @@ class SizebooruUserExtractor(SizebooruExtractor):
     """Extractor for a sizebooru user's uploads"""
     subcategory = "user"
     directory_fmt = ("{category}", "Uploads {user}")
-    pattern = rf"{BASE_PATTERN}/Profile/Uploads/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/Profile/Uploads/([^/?#]+)"
     example = "https://sizebooru.com/Profile/Uploads/USER"
 
     def posts(self):
@@ -153,7 +153,7 @@ class SizebooruFavoriteExtractor(SizebooruExtractor):
     """Extractor for a sizebooru user's favorites"""
     subcategory = "favorite"
     directory_fmt = ("{category}", "Favorites {user}")
-    pattern = rf"{BASE_PATTERN}/Profile/Favorites/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/Profile/Favorites/([^/?#]+)"
     example = "https://sizebooru.com/Profile/Favorites/USER"
 
     def posts(self):
diff --git a/gallery_dl/extractor/skeb.py b/gallery_dl/extractor/skeb.py
index 43e518ef..3c0ae552 100644
--- a/gallery_dl/extractor/skeb.py
+++ b/gallery_dl/extractor/skeb.py
@@ -10,7 +10,7 @@ from .common import Extractor, Message, Dispatch
 from .. import text
 
 BASE_PATTERN = r"(?:https?://)?skeb\.jp"
-USER_PATTERN = rf"{BASE_PATTERN}/@([^/?#]+)"
+USER_PATTERN = BASE_PATTERN + r"/@([^/?#]+)"
 
 
 class SkebExtractor(Extractor):
@@ -194,7 +194,7 @@ class SkebExtractor(Extractor):
 class SkebPostExtractor(SkebExtractor):
     """Extractor for a single skeb post"""
     subcategory = "post"
-    pattern = rf"{USER_PATTERN}/works/(\d+)"
+    pattern = USER_PATTERN + r"/works/(\d+)"
     example = "https://skeb.jp/@USER/works/123"
 
     def posts(self):
@@ -204,7 +204,7 @@ class SkebPostExtractor(SkebExtractor):
 class SkebWorksExtractor(SkebExtractor):
     """Extractor for a skeb user's works"""
     subcategory = "works"
-    pattern = rf"{USER_PATTERN}/works"
+    pattern = USER_PATTERN + r"/works"
     example = "https://skeb.jp/@USER/works"
 
     def posts(self):
@@ -216,7 +216,7 @@ class SkebWorksExtractor(SkebExtractor):
 class SkebSentrequestsExtractor(SkebExtractor):
     """Extractor for a skeb user's sent requests"""
     subcategory = "sentrequests"
-    pattern = rf"{USER_PATTERN}/sent[ _-]?requests"
+    pattern = USER_PATTERN + r"/sent[ _-]?requests"
     example = "https://skeb.jp/@USER/sentrequests"
 
     def posts(self):
@@ -227,7 +227,7 @@ class SkebSentrequestsExtractor(SkebExtractor):
 
 class SkebUserExtractor(Dispatch, SkebExtractor):
     """Extractor for a skeb user profile"""
-    pattern = rf"{USER_PATTERN}/?$"
+    pattern = USER_PATTERN + r"/?$"
     example = "https://skeb.jp/@USER"
 
     def items(self):
@@ -246,7 +246,7 @@ class SkebUserExtractor(Dispatch, SkebExtractor):
 class SkebSearchExtractor(SkebExtractor):
     """Extractor for skeb search results"""
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/search\?q=([^&#]+)"
+    pattern = BASE_PATTERN + r"/search\?q=([^&#]+)"
     example = "https://skeb.jp/search?q=QUERY"
 
     def metadata(self):
@@ -298,7 +298,7 @@ class SkebSearchExtractor(SkebExtractor):
 class SkebFollowingExtractor(SkebExtractor):
     """Extractor for all creators followed by a skeb user"""
     subcategory = "following"
-    pattern = rf"{USER_PATTERN}/following_creators"
+    pattern = USER_PATTERN + r"/following_creators"
     example = "https://skeb.jp/@USER/following_creators"
 
     items = SkebExtractor.items_users
@@ -312,7 +312,7 @@ class SkebFollowingExtractor(SkebExtractor):
 class SkebFollowingUsersExtractor(SkebExtractor):
     """Extractor for your followed users"""
     subcategory = "following-users"
-    pattern = rf"{BASE_PATTERN}/following_users"
+    pattern = BASE_PATTERN + r"/following_users"
     example = "https://skeb.jp/following_users"
 
     items = SkebExtractor.items_users
diff --git a/gallery_dl/extractor/slickpic.py b/gallery_dl/extractor/slickpic.py
index 6f723c80..ef78da32 100644
--- a/gallery_dl/extractor/slickpic.py
+++ b/gallery_dl/extractor/slickpic.py
@@ -32,7 +32,7 @@ class SlickpicAlbumExtractor(SlickpicExtractor):
                      "{album[id]} {album[title]}")
     filename_fmt = "{num:>03}_{id}{title:?_//}.{extension}"
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}/albums/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/albums/([^/?#]+)"
     example = "https://USER.slickpic.com/albums/TITLE/"
 
     def __init__(self, match):
@@ -110,7 +110,7 @@ class SlickpicAlbumExtractor(SlickpicExtractor):
 
 class SlickpicUserExtractor(SlickpicExtractor):
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}(?:/gallery)?/?(?:$|[?#])"
+    pattern = BASE_PATTERN + r"(?:/gallery)?/?(?:$|[?#])"
     example = "https://USER.slickpic.com/"
 
     def items(self):
diff --git a/gallery_dl/extractor/smugmug.py b/gallery_dl/extractor/smugmug.py
index 902044ca..23a4ee72 100644
--- a/gallery_dl/extractor/smugmug.py
+++ b/gallery_dl/extractor/smugmug.py
@@ -93,7 +93,7 @@ class SmugmugImageExtractor(SmugmugExtractor):
     """Extractor for individual smugmug images"""
     subcategory = "image"
     archive_fmt = "{Image[ImageKey]}"
-    pattern = rf"{BASE_PATTERN}(?:/[^/?#]+)+/i-([^/?#-]+)"
+    pattern = BASE_PATTERN + r"(?:/[^/?#]+)+/i-([^/?#-]+)"
     example = "https://USER.smugmug.com/PATH/i-ID"
 
     def __init__(self, match):
@@ -114,7 +114,7 @@ class SmugmugImageExtractor(SmugmugExtractor):
 class SmugmugPathExtractor(SmugmugExtractor):
     """Extractor for smugmug albums from URL paths and users"""
     subcategory = "path"
-    pattern = rf"{BASE_PATTERN}((?:/[^/?#a-fh-mo-z][^/?#]*)*)/?$"
+    pattern = BASE_PATTERN + r"((?:/[^/?#a-fh-mo-z][^/?#]*)*)/?$"
     example = "https://USER.smugmug.com/PATH"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/soundgasm.py b/gallery_dl/extractor/soundgasm.py
index a4617dd2..18856143 100644
--- a/gallery_dl/extractor/soundgasm.py
+++ b/gallery_dl/extractor/soundgasm.py
@@ -50,7 +50,7 @@ class SoundgasmExtractor(Extractor):
 class SoundgasmAudioExtractor(SoundgasmExtractor):
     """Extractor for audio clips from soundgasm.net"""
     subcategory = "audio"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/([^/?#]+)"
     example = "https://soundgasm.net/u/USER/TITLE"
 
     def __init__(self, match):
@@ -64,7 +64,7 @@ class SoundgasmAudioExtractor(SoundgasmExtractor):
 class SoundgasmUserExtractor(SoundgasmExtractor):
     """Extractor for all sounds from a soundgasm user"""
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/?$"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/?$"
     example = "https://soundgasm.net/u/USER"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/steamgriddb.py b/gallery_dl/extractor/steamgriddb.py
index c3af7fd6..371f4e26 100644
--- a/gallery_dl/extractor/steamgriddb.py
+++ b/gallery_dl/extractor/steamgriddb.py
@@ -157,7 +157,7 @@ class SteamgriddbAssetsExtractor(SteamgriddbExtractor):
 class SteamgriddbAssetExtractor(SteamgriddbExtractor):
     """Extractor for a single asset"""
     subcategory = "asset"
-    pattern = rf"{BASE_PATTERN}/(grid|hero|logo|icon)/(\d+)"
+    pattern = BASE_PATTERN + r"/(grid|hero|logo|icon)/(\d+)"
     example = "https://www.steamgriddb.com/grid/1234"
 
     def __init__(self, match):
@@ -177,7 +177,7 @@ class SteamgriddbAssetExtractor(SteamgriddbExtractor):
 class SteamgriddbGridsExtractor(SteamgriddbAssetsExtractor):
     subcategory = "grids"
     asset_type = "grid"
-    pattern = rf"{BASE_PATTERN}/(game|collection)/(\d+)/grids(?:/(\d+))?"
+    pattern = BASE_PATTERN + r"/(game|collection)/(\d+)/grids(?:/(\d+))?"
     example = "https://www.steamgriddb.com/game/1234/grids"
     valid_dimensions = ("460x215", "920x430", "600x900", "342x482", "660x930",
                         "512x512", "1024x1024")
@@ -189,7 +189,7 @@ class SteamgriddbGridsExtractor(SteamgriddbAssetsExtractor):
 class SteamgriddbHeroesExtractor(SteamgriddbAssetsExtractor):
     subcategory = "heroes"
     asset_type = "hero"
-    pattern = rf"{BASE_PATTERN}/(game|collection)/(\d+)/heroes(?:/(\d+))?"
+    pattern = BASE_PATTERN + r"/(game|collection)/(\d+)/heroes(?:/(\d+))?"
     example = "https://www.steamgriddb.com/game/1234/heroes"
     valid_dimensions = ("1920x620", "3840x1240", "1600x650")
     valid_styles = ("alternate", "blurred", "material")
@@ -199,7 +199,7 @@ class SteamgriddbHeroesExtractor(SteamgriddbAssetsExtractor):
 class SteamgriddbLogosExtractor(SteamgriddbAssetsExtractor):
     subcategory = "logos"
     asset_type = "logo"
-    pattern = rf"{BASE_PATTERN}/(game|collection)/(\d+)/logos(?:/(\d+))?"
+    pattern = BASE_PATTERN + r"/(game|collection)/(\d+)/logos(?:/(\d+))?"
     example = "https://www.steamgriddb.com/game/1234/logos"
     valid_dimensions = None
     valid_styles = ("official", "white", "black", "custom")
@@ -209,7 +209,7 @@ class SteamgriddbLogosExtractor(SteamgriddbAssetsExtractor):
 class SteamgriddbIconsExtractor(SteamgriddbAssetsExtractor):
     subcategory = "icons"
     asset_type = "icon"
-    pattern = rf"{BASE_PATTERN}/(game|collection)/(\d+)/icons(?:/(\d+))?"
+    pattern = BASE_PATTERN + r"/(game|collection)/(\d+)/icons(?:/(\d+))?"
     example = "https://www.steamgriddb.com/game/1234/icons"
     valid_dimensions = [f"{i}x{i}" for i in (8, 10, 14, 16, 20, 24,
                         28, 32, 35, 40, 48, 54, 56, 57, 60, 64, 72, 76, 80, 90,
diff --git a/gallery_dl/extractor/subscribestar.py b/gallery_dl/extractor/subscribestar.py
index 6f4ace7e..68800a32 100644
--- a/gallery_dl/extractor/subscribestar.py
+++ b/gallery_dl/extractor/subscribestar.py
@@ -58,7 +58,7 @@ class SubscribestarExtractor(Extractor):
                     text.nameext_from_url(url, item)
 
                 if url[0] == "/":
-                    url = f"{self.root}{url}"
+                    url = self.root + url
                 yield Message.Url, url, item
 
     def posts(self):
@@ -72,7 +72,7 @@ class SubscribestarExtractor(Extractor):
                     "/verify_subscriber" in response.url or
                     "/age_confirmation_warning" in response.url):
                 raise exception.AbortExtraction(
-                    f"HTTP redirect to {response.url}")
+                    "HTTP redirect to " + response.url)
 
             content = response.content
             if len(content) < 250 and b">redirected<" in content:
@@ -250,7 +250,7 @@ class SubscribestarUserTagExtractor(SubscribestarExtractor):
 class SubscribestarUserExtractor(SubscribestarExtractor):
     """Extractor for media from a subscribestar user"""
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/(?!posts/)([^/?#]+)"
+    pattern = BASE_PATTERN + r"/(?!posts/)([^/?#]+)"
     example = "https://www.subscribestar.com/USER"
 
     def posts(self):
@@ -260,7 +260,7 @@ class SubscribestarUserExtractor(SubscribestarExtractor):
 class SubscribestarPostExtractor(SubscribestarExtractor):
     """Extractor for media from a single subscribestar post"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/posts/(\d+)"
+    pattern = BASE_PATTERN + r"/posts/(\d+)"
     example = "https://www.subscribestar.com/posts/12345"
 
     def posts(self):
diff --git a/gallery_dl/extractor/szurubooru.py b/gallery_dl/extractor/szurubooru.py
index 59477cc3..2bf4a61e 100644
--- a/gallery_dl/extractor/szurubooru.py
+++ b/gallery_dl/extractor/szurubooru.py
@@ -93,7 +93,7 @@ class SzurubooruTagExtractor(SzurubooruExtractor):
     subcategory = "tag"
     directory_fmt = ("{category}", "{search_tags}")
     archive_fmt = "t_{search_tags}_{id}_{version}"
-    pattern = rf"{BASE_PATTERN}/posts(?:/query=([^/?#]*))?"
+    pattern = BASE_PATTERN + r"/posts(?:/query=([^/?#]*))?"
     example = "https://booru.bcbnsfw.space/posts/query=TAG"
 
     def __init__(self, match):
@@ -116,7 +116,7 @@ class SzurubooruTagExtractor(SzurubooruExtractor):
 class SzurubooruPostExtractor(SzurubooruExtractor):
     subcategory = "post"
     archive_fmt = "{id}_{version}"
-    pattern = rf"{BASE_PATTERN}/post/(\d+)"
+    pattern = BASE_PATTERN + r"/post/(\d+)"
     example = "https://booru.bcbnsfw.space/post/12345"
 
     def posts(self):
diff --git a/gallery_dl/extractor/tapas.py b/gallery_dl/extractor/tapas.py
index 5f8cb67b..b7baccce 100644
--- a/gallery_dl/extractor/tapas.py
+++ b/gallery_dl/extractor/tapas.py
@@ -72,7 +72,7 @@ class TapasExtractor(Extractor):
 
 class TapasEpisodeExtractor(TapasExtractor):
     subcategory = "episode"
-    pattern = rf"{BASE_PATTERN}/episode/(\d+)"
+    pattern = BASE_PATTERN + r"/episode/(\d+)"
     example = "https://tapas.io/episode/12345"
 
     def items(self):
@@ -116,7 +116,7 @@ class TapasEpisodeExtractor(TapasExtractor):
 
 class TapasSeriesExtractor(TapasExtractor):
     subcategory = "series"
-    pattern = rf"{BASE_PATTERN}/series/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/series/([^/?#]+)"
     example = "https://tapas.io/series/TITLE"
 
     def items(self):
@@ -150,7 +150,7 @@ class TapasSeriesExtractor(TapasExtractor):
 
 class TapasCreatorExtractor(TapasExtractor):
     subcategory = "creator"
-    pattern = rf"{BASE_PATTERN}/(?!series|episode)([^/?#]+)"
+    pattern = BASE_PATTERN + r"/(?!series|episode)([^/?#]+)"
     example = "https://tapas.io/CREATOR"
 
     def items(self):
diff --git a/gallery_dl/extractor/tcbscans.py b/gallery_dl/extractor/tcbscans.py
index e27ef0d7..6dcb153c 100644
--- a/gallery_dl/extractor/tcbscans.py
+++ b/gallery_dl/extractor/tcbscans.py
@@ -15,7 +15,7 @@ BASE_PATTERN = (r"(?:https?://)?(?:tcb(?:-backup\.bihar-mirchi|scans)"
 
 class TcbscansChapterExtractor(ChapterExtractor):
     category = "tcbscans"
-    pattern = rf"{BASE_PATTERN}(/chapters/\d+/[^/?#]+)"
+    pattern = BASE_PATTERN + r"(/chapters/\d+/[^/?#]+)"
     example = "https://tcbscans.me/chapters/12345/MANGA-chapter-123"
 
     def __init__(self, match):
@@ -44,7 +44,7 @@ class TcbscansChapterExtractor(ChapterExtractor):
 class TcbscansMangaExtractor(MangaExtractor):
     category = "tcbscans"
     chapterclass = TcbscansChapterExtractor
-    pattern = rf"{BASE_PATTERN}(/mangas/\d+/[^/?#]+)"
+    pattern = BASE_PATTERN + r"(/mangas/\d+/[^/?#]+)"
     example = "https://tcbscans.me/mangas/123/MANGA"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/tenor.py b/gallery_dl/extractor/tenor.py
index 3e4bab08..1edc3612 100644
--- a/gallery_dl/extractor/tenor.py
+++ b/gallery_dl/extractor/tenor.py
@@ -111,7 +111,7 @@ class TenorExtractor(Extractor):
 
 class TenorImageExtractor(TenorExtractor):
     subcategory = "image"
-    pattern = rf"{BASE_PATTERN}view/(?:[^/?#]*-)?(\d+)"
+    pattern = BASE_PATTERN + r"view/(?:[^/?#]*-)?(\d+)"
     example = "https://tenor.com/view/SLUG-1234567890"
 
     def gifs(self):
@@ -125,7 +125,7 @@ class TenorImageExtractor(TenorExtractor):
 class TenorSearchExtractor(TenorExtractor):
     subcategory = "search"
     directory_fmt = ("{category}", "{search_tags}")
-    pattern = rf"{BASE_PATTERN}search/([^/?#]+)"
+    pattern = BASE_PATTERN + r"search/([^/?#]+)"
     example = "https://tenor.com/search/QUERY"
 
     def gifs(self):
@@ -141,7 +141,7 @@ class TenorSearchExtractor(TenorExtractor):
 class TenorUserExtractor(TenorExtractor):
     subcategory = "user"
     directory_fmt = ("{category}", "@{user[username]}")
-    pattern = rf"{BASE_PATTERN}(?:users|official)/([^/?#]+)"
+    pattern = BASE_PATTERN + r"(?:users|official)/([^/?#]+)"
     example = "https://tenor.com/users/USER"
 
     def gifs(self):
diff --git a/gallery_dl/extractor/thehentaiworld.py b/gallery_dl/extractor/thehentaiworld.py
index 773f3003..f1b4ee34 100644
--- a/gallery_dl/extractor/thehentaiworld.py
+++ b/gallery_dl/extractor/thehentaiworld.py
@@ -90,12 +90,12 @@ class ThehentaiworldExtractor(Extractor):
         post["tags"] = tags_list = []
         for key, value in tags.items():
             tags_list.extend(value)
-            post[f"tags_{key}" if key else "tags_general"] = value
+            post["tags_" + key if key else "tags_general"] = value
 
         return post
 
     def _pagination(self, endpoint):
-        base = f"{self.root}{endpoint}"
+        base = self.root + endpoint
         pnum = self.page_start
 
         while True:
@@ -116,7 +116,7 @@ class ThehentaiworldTagExtractor(ThehentaiworldExtractor):
     page_start = 1
     post_start = 0
     directory_fmt = ("{category}", "{search_tags}")
-    pattern = rf"{BASE_PATTERN}/tag/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/tag/([^/?#]+)"
     example = "https://thehentaiworld.com/tag/TAG/"
 
     def posts(self):
@@ -132,8 +132,8 @@ class ThehentaiworldTagExtractor(ThehentaiworldExtractor):
 
 class ThehentaiworldPostExtractor(ThehentaiworldExtractor):
     subcategory = "post"
-    pattern = (rf"{BASE_PATTERN}("
-               rf"/(?:video|(?:[\w-]+-)?hentai-image)s/([^/?#]+))")
+    pattern = (BASE_PATTERN +
+               r"(/(?:video|(?:[\w-]+-)?hentai-image)s/([^/?#]+))")
     example = "https://thehentaiworld.com/hentai-images/SLUG/"
 
     def posts(self):
diff --git a/gallery_dl/extractor/tiktok.py b/gallery_dl/extractor/tiktok.py
index a4c71712..49d60b0c 100644
--- a/gallery_dl/extractor/tiktok.py
+++ b/gallery_dl/extractor/tiktok.py
@@ -193,7 +193,7 @@ class TiktokExtractor(Extractor):
 class TiktokPostExtractor(TiktokExtractor):
     """Extract a single video or photo TikTok link"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/(?:@([\w_.-]*)|share)/(?:phot|vide)o/(\d+)"
+    pattern = BASE_PATTERN + r"/(?:@([\w_.-]*)|share)/(?:phot|vide)o/(\d+)"
     example = "https://www.tiktok.com/@USER/photo/1234567890"
 
     def urls(self):
@@ -226,7 +226,7 @@ class TiktokVmpostExtractor(TiktokExtractor):
 class TiktokUserExtractor(TiktokExtractor):
     """Extract a TikTok user's profile"""
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/@([\w_.-]+)/?(?:$|\?|#)"
+    pattern = BASE_PATTERN + r"/@([\w_.-]+)/?(?:$|\?|#)"
     example = "https://www.tiktok.com/@USER"
 
     def _init(self):
diff --git a/gallery_dl/extractor/tmohentai.py b/gallery_dl/extractor/tmohentai.py
index 873cce8b..ef441d34 100644
--- a/gallery_dl/extractor/tmohentai.py
+++ b/gallery_dl/extractor/tmohentai.py
@@ -16,7 +16,7 @@ class TmohentaiGalleryExtractor(GalleryExtractor):
     category = "tmohentai"
     root = "http://tmohentai.com"
     directory_fmt = ("{category}", "{title} ({gallery_id})")
-    pattern = rf"{BASE_PATTERN}/(?:contents|reader)/(\w+)"
+    pattern = BASE_PATTERN + r"/(?:contents|reader)/(\w+)"
     example = "https://tmohentai.com/contents/12345a67b89c0"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/toyhouse.py b/gallery_dl/extractor/toyhouse.py
index cc29b116..acf1749e 100644
--- a/gallery_dl/extractor/toyhouse.py
+++ b/gallery_dl/extractor/toyhouse.py
@@ -104,7 +104,7 @@ class ToyhouseExtractor(Extractor):
 class ToyhouseArtExtractor(ToyhouseExtractor):
     """Extractor for artworks of a toyhouse user"""
     subcategory = "art"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/art"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/art"
     example = "https://www.toyhou.se/USER/art"
 
     def posts(self):
diff --git a/gallery_dl/extractor/tsumino.py b/gallery_dl/extractor/tsumino.py
index 1ccdafb1..2ac7e42f 100644
--- a/gallery_dl/extractor/tsumino.py
+++ b/gallery_dl/extractor/tsumino.py
@@ -30,7 +30,7 @@ class TsuminoBase():
     @cache(maxage=14*86400, keyarg=1)
     def _login_impl(self, username, password):
         self.log.info("Logging in as %s", username)
-        url = f"{self.root}/Account/Login"
+        url = self.root + "/Account/Login"
         headers = {"Referer": url}
         data = {"Username": username, "Password": password}
 
@@ -119,9 +119,9 @@ class TsuminoSearchExtractor(TsuminoBase, Extractor):
 
     def galleries(self):
         """Return all gallery results matching 'self.query'"""
-        url = f"{self.root}/Search/Operate?type=Book"
+        url = self.root + "/Search/Operate?type=Book"
         headers = {
-            "Referer": f"{self.root}/",
+            "Referer": self.root + "/",
             "X-Requested-With": "XMLHttpRequest",
         }
         data = {
diff --git a/gallery_dl/extractor/tumblr.py b/gallery_dl/extractor/tumblr.py
index 5bb5a40b..bd274168 100644
--- a/gallery_dl/extractor/tumblr.py
+++ b/gallery_dl/extractor/tumblr.py
@@ -32,7 +32,7 @@ class TumblrExtractor(Extractor):
 
     def _init(self):
         if name := self.groups[1]:
-            self.blog = f"{name}.tumblr.com"
+            self.blog = name + ".tumblr.com"
         else:
             self.blog = self.groups[0] or self.groups[2]
 
@@ -270,7 +270,7 @@ class TumblrExtractor(Extractor):
 class TumblrUserExtractor(TumblrExtractor):
     """Extractor for a Tumblr user's posts"""
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}(?:/page/\d+|/archive)?/?$"
+    pattern = BASE_PATTERN + r"(?:/page/\d+|/archive)?/?$"
     example = "https://www.tumblr.com/BLOG"
 
     def posts(self):
@@ -280,7 +280,7 @@ class TumblrUserExtractor(TumblrExtractor):
 class TumblrPostExtractor(TumblrExtractor):
     """Extractor for a single Tumblr post"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/(?:post/|image/)?(\d+)"
+    pattern = BASE_PATTERN + r"/(?:post/|image/)?(\d+)"
     example = "https://www.tumblr.com/BLOG/12345"
 
     def posts(self):
@@ -295,7 +295,7 @@ class TumblrPostExtractor(TumblrExtractor):
 class TumblrTagExtractor(TumblrExtractor):
     """Extractor for Tumblr user's posts by tag"""
     subcategory = "tag"
-    pattern = rf"{BASE_PATTERN}(?:/archive)?/tagged/([^/?#]+)"
+    pattern = BASE_PATTERN + r"(?:/archive)?/tagged/([^/?#]+)"
     example = "https://www.tumblr.com/BLOG/tagged/TAG"
 
     def posts(self):
@@ -307,7 +307,7 @@ class TumblrTagExtractor(TumblrExtractor):
 class TumblrDayExtractor(TumblrExtractor):
     """Extractor for Tumblr user's posts by day"""
     subcategory = "day"
-    pattern = rf"{BASE_PATTERN}/day/(\d\d\d\d/\d\d/\d\d)"
+    pattern = BASE_PATTERN + r"/day/(\d\d\d\d/\d\d/\d\d)"
     example = "https://www.tumblr.com/BLOG/day/1970/01/01"
 
     def posts(self):
@@ -325,7 +325,7 @@ class TumblrLikesExtractor(TumblrExtractor):
     subcategory = "likes"
     directory_fmt = ("{category}", "{blog_name}", "likes")
     archive_fmt = "f_{blog[name]}_{id}_{num}"
-    pattern = rf"{BASE_PATTERN}/likes"
+    pattern = BASE_PATTERN + r"/likes"
     example = "https://www.tumblr.com/BLOG/likes"
 
     def posts(self):
@@ -335,7 +335,7 @@ class TumblrLikesExtractor(TumblrExtractor):
 class TumblrFollowingExtractor(TumblrExtractor):
     """Extractor for a Tumblr user's followed blogs"""
     subcategory = "following"
-    pattern = rf"{BASE_PATTERN}/following"
+    pattern = BASE_PATTERN + r"/following"
     example = "https://www.tumblr.com/BLOG/following"
 
     items = TumblrExtractor.items_blogs
@@ -347,7 +347,7 @@ class TumblrFollowingExtractor(TumblrExtractor):
 class TumblrFollowersExtractor(TumblrExtractor):
     """Extractor for a Tumblr user's followers"""
     subcategory = "followers"
-    pattern = rf"{BASE_PATTERN}/followers"
+    pattern = BASE_PATTERN + r"/followers"
     example = "https://www.tumblr.com/BLOG/followers"
 
     items = TumblrExtractor.items_blogs
diff --git a/gallery_dl/extractor/tumblrgallery.py b/gallery_dl/extractor/tumblrgallery.py
index 68c9ec79..26868ecc 100644
--- a/gallery_dl/extractor/tumblrgallery.py
+++ b/gallery_dl/extractor/tumblrgallery.py
@@ -36,7 +36,7 @@ class TumblrgalleryExtractor(GalleryExtractor):
 class TumblrgalleryTumblrblogExtractor(TumblrgalleryExtractor):
     """Extractor for Tumblrblog on tumblrgallery.xyz"""
     subcategory = "tumblrblog"
-    pattern = rf"{BASE_PATTERN}(/tumblrblog/gallery/(\d+)\.html)"
+    pattern = BASE_PATTERN + r"(/tumblrblog/gallery/(\d+)\.html)"
     example = "https://tumblrgallery.xyz/tumblrblog/gallery/12345.html"
 
     def __init__(self, match):
@@ -68,7 +68,7 @@ class TumblrgalleryTumblrblogExtractor(TumblrgalleryExtractor):
 class TumblrgalleryPostExtractor(TumblrgalleryExtractor):
     """Extractor for Posts on tumblrgallery.xyz"""
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}(/post/(\d+)\.html)"
+    pattern = BASE_PATTERN + r"(/post/(\d+)\.html)"
     example = "https://tumblrgallery.xyz/post/12345.html"
 
     def __init__(self, match):
@@ -93,7 +93,7 @@ class TumblrgallerySearchExtractor(TumblrgalleryExtractor):
     subcategory = "search"
     filename_fmt = "{category}_{num:>03}_{gallery_id}_{id}_{title}.{extension}"
     directory_fmt = ("{category}", "{search_term}")
-    pattern = rf"{BASE_PATTERN}(/s\.php\?q=([^&#]+))"
+    pattern = BASE_PATTERN + r"(/s\.php\?q=([^&#]+))"
     example = "https://tumblrgallery.xyz/s.php?q=QUERY"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/tungsten.py b/gallery_dl/extractor/tungsten.py
index 67c0b508..8f2b55d1 100644
--- a/gallery_dl/extractor/tungsten.py
+++ b/gallery_dl/extractor/tungsten.py
@@ -52,7 +52,7 @@ class TungstenExtractor(Extractor):
 
 class TungstenPostExtractor(TungstenExtractor):
     subcategory = "post"
-    pattern = rf"{BASE_PATTERN}/post/(\w+)"
+    pattern = BASE_PATTERN + r"/post/(\w+)"
     example = "https://tungsten.run/post/AbCdEfGhIjKlMnOp"
 
     def posts(self):
@@ -64,7 +64,7 @@ class TungstenPostExtractor(TungstenExtractor):
 
 class TungstenModelExtractor(TungstenExtractor):
     subcategory = "model"
-    pattern = rf"{BASE_PATTERN}/model/(\w+)(?:/?\?model_version=(\w+))?"
+    pattern = BASE_PATTERN + r"/model/(\w+)(?:/?\?model_version=(\w+))?"
     example = "https://tungsten.run/model/AbCdEfGhIjKlM"
 
     def posts(self):
@@ -87,7 +87,7 @@ class TungstenModelExtractor(TungstenExtractor):
 
 class TungstenUserExtractor(TungstenExtractor):
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/user/([^/?#]+)(?:/posts)?/?(?:\?([^#]+))?"
+    pattern = BASE_PATTERN + r"/user/([^/?#]+)(?:/posts)?/?(?:\?([^#]+))?"
     example = "https://tungsten.run/user/USER"
 
     def posts(self):
diff --git a/gallery_dl/extractor/twibooru.py b/gallery_dl/extractor/twibooru.py
index e21ef2a3..4558e212 100644
--- a/gallery_dl/extractor/twibooru.py
+++ b/gallery_dl/extractor/twibooru.py
@@ -48,7 +48,7 @@ class TwibooruPostExtractor(TwibooruExtractor):
     """Extractor for single twibooru posts"""
     subcategory = "post"
     request_interval = (0.5, 1.5)
-    pattern = rf"{BASE_PATTERN}/(\d+)"
+    pattern = BASE_PATTERN + r"/(\d+)"
     example = "https://twibooru.org/12345"
 
     def __init__(self, match):
@@ -63,7 +63,7 @@ class TwibooruSearchExtractor(TwibooruExtractor):
     """Extractor for twibooru search results"""
     subcategory = "search"
     directory_fmt = ("{category}", "{search_tags}")
-    pattern = rf"{BASE_PATTERN}/(?:search/?\?([^#]+)|tags/([^/?#]+))"
+    pattern = BASE_PATTERN + r"/(?:search/?\?([^#]+)|tags/([^/?#]+))"
     example = "https://twibooru.org/search?q=TAG"
 
     def __init__(self, match):
@@ -97,7 +97,7 @@ class TwibooruGalleryExtractor(TwibooruExtractor):
     subcategory = "gallery"
     directory_fmt = ("{category}", "galleries",
                      "{gallery[id]} {gallery[title]}")
-    pattern = rf"{BASE_PATTERN}/galleries/(\d+)"
+    pattern = BASE_PATTERN + r"/galleries/(\d+)"
     example = "https://twibooru.org/galleries/12345"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/twitter.py b/gallery_dl/extractor/twitter.py
index 546e8e18..739400b4 100644
--- a/gallery_dl/extractor/twitter.py
+++ b/gallery_dl/extractor/twitter.py
@@ -16,7 +16,7 @@ import random
 
 BASE_PATTERN = (r"(?:https?://)?(?:www\.|mobile\.)?"
                 r"(?:(?:[fv]x)?twitter|(?:fix(?:up|v))?x)\.com")
-USER_PATTERN = rf"{BASE_PATTERN}/([^/?#]+)"
+USER_PATTERN = BASE_PATTERN + r"/([^/?#]+)"
 
 
 class TwitterExtractor(Extractor):
@@ -667,8 +667,8 @@ class TwitterExtractor(Extractor):
 class TwitterHomeExtractor(TwitterExtractor):
     """Extractor for Twitter home timelines"""
     subcategory = "home"
-    pattern = (rf"{BASE_PATTERN}/"
-               rf"(?:home(?:/fo(?:llowing|r[-_ ]?you()))?|i/timeline)/?$")
+    pattern = (BASE_PATTERN +
+               r"/(?:home(?:/fo(?:llowing|r[-_ ]?you()))?|i/timeline)/?$")
     example = "https://x.com/home"
 
     def tweets(self):
@@ -680,7 +680,7 @@ class TwitterHomeExtractor(TwitterExtractor):
 class TwitterSearchExtractor(TwitterExtractor):
     """Extractor for Twitter search results"""
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/search/?\?(?:[^&#]+&)*q=([^&#]+)"
+    pattern = BASE_PATTERN + r"/search/?\?(?:[^&#]+&)*q=([^&#]+)"
     example = "https://x.com/search?q=QUERY"
 
     def metadata(self):
@@ -711,7 +711,7 @@ class TwitterSearchExtractor(TwitterExtractor):
 class TwitterHashtagExtractor(TwitterExtractor):
     """Extractor for Twitter hashtags"""
     subcategory = "hashtag"
-    pattern = rf"{BASE_PATTERN}/hashtag/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/hashtag/([^/?#]+)"
     example = "https://x.com/hashtag/NAME"
 
     def items(self):
@@ -722,7 +722,7 @@ class TwitterHashtagExtractor(TwitterExtractor):
 
 class TwitterUserExtractor(Dispatch, TwitterExtractor):
     """Extractor for a Twitter user"""
-    pattern = (rf"{BASE_PATTERN}/(?:"
+    pattern = (BASE_PATTERN + r"/(?:"
                r"([^/?#]+)/?(?:$|\?|#)"
                r"|i(?:/user/|ntent/user\?user_id=)(\d+))")
     example = "https://x.com/USER"
@@ -730,26 +730,26 @@ class TwitterUserExtractor(Dispatch, TwitterExtractor):
     def items(self):
         user, user_id = self.groups
         if user_id is not None:
-            user = f"id:{user_id}"
+            user = "id:" + user_id
 
         base = f"{self.root}/{user}/"
         return self._dispatch_extractors((
-            (TwitterInfoExtractor      , f"{base}info"),
-            (TwitterAvatarExtractor    , f"{base}photo"),
-            (TwitterBackgroundExtractor, f"{base}header_photo"),
-            (TwitterTimelineExtractor  , f"{base}timeline"),
-            (TwitterTweetsExtractor    , f"{base}tweets"),
-            (TwitterMediaExtractor     , f"{base}media"),
-            (TwitterRepliesExtractor   , f"{base}with_replies"),
-            (TwitterHighlightsExtractor, f"{base}highlights"),
-            (TwitterLikesExtractor     , f"{base}likes"),
+            (TwitterInfoExtractor      , base + "info"),
+            (TwitterAvatarExtractor    , base + "photo"),
+            (TwitterBackgroundExtractor, base + "header_photo"),
+            (TwitterTimelineExtractor  , base + "timeline"),
+            (TwitterTweetsExtractor    , base + "tweets"),
+            (TwitterMediaExtractor     , base + "media"),
+            (TwitterRepliesExtractor   , base + "with_replies"),
+            (TwitterHighlightsExtractor, base + "highlights"),
+            (TwitterLikesExtractor     , base + "likes"),
         ), ("timeline",))
 
 
 class TwitterTimelineExtractor(TwitterExtractor):
     """Extractor for a Twitter user timeline"""
     subcategory = "timeline"
-    pattern = rf"{USER_PATTERN}/timeline(?!\w)"
+    pattern = USER_PATTERN + r"/timeline(?!\w)"
     example = "https://x.com/USER/timeline"
 
     def _init_cursor(self):
@@ -846,7 +846,7 @@ class TwitterTimelineExtractor(TwitterExtractor):
 class TwitterTweetsExtractor(TwitterExtractor):
     """Extractor for Tweets from a user's Tweets timeline"""
     subcategory = "tweets"
-    pattern = rf"{USER_PATTERN}/tweets(?!\w)"
+    pattern = USER_PATTERN + r"/tweets(?!\w)"
     example = "https://x.com/USER/tweets"
 
     def tweets(self):
@@ -856,7 +856,7 @@ class TwitterTweetsExtractor(TwitterExtractor):
 class TwitterRepliesExtractor(TwitterExtractor):
     """Extractor for Tweets from a user's timeline including replies"""
     subcategory = "replies"
-    pattern = rf"{USER_PATTERN}/with_replies(?!\w)"
+    pattern = USER_PATTERN + r"/with_replies(?!\w)"
     example = "https://x.com/USER/with_replies"
 
     def tweets(self):
@@ -866,7 +866,7 @@ class TwitterRepliesExtractor(TwitterExtractor):
 class TwitterHighlightsExtractor(TwitterExtractor):
     """Extractor for Tweets from a user's highlights timeline"""
     subcategory = "highlights"
-    pattern = rf"{USER_PATTERN}/highlights(?!\w)"
+    pattern = USER_PATTERN + r"/highlights(?!\w)"
     example = "https://x.com/USER/highlights"
 
     def tweets(self):
@@ -876,7 +876,7 @@ class TwitterHighlightsExtractor(TwitterExtractor):
 class TwitterMediaExtractor(TwitterExtractor):
     """Extractor for Tweets from a user's Media timeline"""
     subcategory = "media"
-    pattern = rf"{USER_PATTERN}/media(?!\w)"
+    pattern = USER_PATTERN + r"/media(?!\w)"
     example = "https://x.com/USER/media"
 
     def tweets(self):
@@ -886,7 +886,7 @@ class TwitterMediaExtractor(TwitterExtractor):
 class TwitterLikesExtractor(TwitterExtractor):
     """Extractor for liked tweets"""
     subcategory = "likes"
-    pattern = rf"{USER_PATTERN}/likes(?!\w)"
+    pattern = USER_PATTERN + r"/likes(?!\w)"
     example = "https://x.com/USER/likes"
 
     def metadata(self):
@@ -899,7 +899,7 @@ class TwitterLikesExtractor(TwitterExtractor):
 class TwitterBookmarkExtractor(TwitterExtractor):
     """Extractor for bookmarked tweets"""
     subcategory = "bookmark"
-    pattern = rf"{BASE_PATTERN}/i/bookmarks()"
+    pattern = BASE_PATTERN + r"/i/bookmarks()"
     example = "https://x.com/i/bookmarks"
 
     def tweets(self):
@@ -915,7 +915,7 @@ class TwitterBookmarkExtractor(TwitterExtractor):
 class TwitterListExtractor(TwitterExtractor):
     """Extractor for Twitter lists"""
     subcategory = "list"
-    pattern = rf"{BASE_PATTERN}/i/lists/(\d+)/?$"
+    pattern = BASE_PATTERN + r"/i/lists/(\d+)/?$"
     example = "https://x.com/i/lists/12345"
 
     def tweets(self):
@@ -925,7 +925,7 @@ class TwitterListExtractor(TwitterExtractor):
 class TwitterListMembersExtractor(TwitterExtractor):
     """Extractor for members of a Twitter list"""
     subcategory = "list-members"
-    pattern = rf"{BASE_PATTERN}/i/lists/(\d+)/members"
+    pattern = BASE_PATTERN + r"/i/lists/(\d+)/members"
     example = "https://x.com/i/lists/12345/members"
 
     def items(self):
@@ -936,7 +936,7 @@ class TwitterListMembersExtractor(TwitterExtractor):
 class TwitterFollowingExtractor(TwitterExtractor):
     """Extractor for followed users"""
     subcategory = "following"
-    pattern = rf"{USER_PATTERN}/following(?!\w)"
+    pattern = USER_PATTERN + r"/following(?!\w)"
     example = "https://x.com/USER/following"
 
     def items(self):
@@ -947,7 +947,7 @@ class TwitterFollowingExtractor(TwitterExtractor):
 class TwitterFollowersExtractor(TwitterExtractor):
     """Extractor for a user's followers"""
     subcategory = "followers"
-    pattern = rf"{USER_PATTERN}/followers(?!\w)"
+    pattern = USER_PATTERN + r"/followers(?!\w)"
     example = "https://x.com/USER/followers"
 
     def items(self):
@@ -961,7 +961,7 @@ class TwitterCommunityExtractor(TwitterExtractor):
     directory_fmt = ("{category}", "Communities",
                      "{community[name]} ({community[id]})")
     archive_fmt = "C_{community[id]}_{tweet_id}_{num}"
-    pattern = rf"{BASE_PATTERN}/i/communities/(\d+)"
+    pattern = BASE_PATTERN + r"/i/communities/(\d+)"
     example = "https://x.com/i/communities/12345"
 
     def tweets(self):
@@ -975,7 +975,7 @@ class TwitterCommunitiesExtractor(TwitterExtractor):
     subcategory = "communities"
     directory_fmt = TwitterCommunityExtractor.directory_fmt
     archive_fmt = TwitterCommunityExtractor.archive_fmt
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/communities/?$"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/communities/?$"
     example = "https://x.com/i/communities"
 
     def tweets(self):
@@ -987,7 +987,7 @@ class TwitterEventExtractor(TwitterExtractor):
     subcategory = "event"
     directory_fmt = ("{category}", "Events",
                      "{event[id]} {event[short_title]}")
-    pattern = rf"{BASE_PATTERN}/i/events/(\d+)"
+    pattern = BASE_PATTERN + r"/i/events/(\d+)"
     example = "https://x.com/i/events/12345"
 
     def metadata(self):
@@ -1000,7 +1000,7 @@ class TwitterEventExtractor(TwitterExtractor):
 class TwitterTweetExtractor(TwitterExtractor):
     """Extractor for individual tweets"""
     subcategory = "tweet"
-    pattern = (rf"{BASE_PATTERN}/([^/?#]+|i/web)/status/(\d+)"
+    pattern = (BASE_PATTERN + r"/([^/?#]+|i/web)/status/(\d+)"
                r"/?(?:$|\?|#|photo/|video/)")
     example = "https://x.com/USER/status/12345"
 
@@ -1081,7 +1081,7 @@ class TwitterTweetExtractor(TwitterExtractor):
 class TwitterQuotesExtractor(TwitterExtractor):
     """Extractor for quotes of a Tweet"""
     subcategory = "quotes"
-    pattern = rf"{BASE_PATTERN}/(?:[^/?#]+|i/web)/status/(\d+)/quotes"
+    pattern = BASE_PATTERN + r"/(?:[^/?#]+|i/web)/status/(\d+)/quotes"
     example = "https://x.com/USER/status/12345/quotes"
 
     def items(self):
@@ -1093,7 +1093,7 @@ class TwitterQuotesExtractor(TwitterExtractor):
 class TwitterInfoExtractor(TwitterExtractor):
     """Extractor for a user's profile data"""
     subcategory = "info"
-    pattern = rf"{USER_PATTERN}/info"
+    pattern = USER_PATTERN + r"/info"
     example = "https://x.com/USER/info"
 
     def items(self):
@@ -1112,7 +1112,7 @@ class TwitterAvatarExtractor(TwitterExtractor):
     subcategory = "avatar"
     filename_fmt = "avatar {date}.{extension}"
     archive_fmt = "AV_{user[id]}_{date}"
-    pattern = rf"{USER_PATTERN}/photo"
+    pattern = USER_PATTERN + r"/photo"
     example = "https://x.com/USER/photo"
 
     def tweets(self):
@@ -1134,7 +1134,7 @@ class TwitterBackgroundExtractor(TwitterExtractor):
     subcategory = "background"
     filename_fmt = "background {date}.{extension}"
     archive_fmt = "BG_{user[id]}_{date}"
-    pattern = rf"{USER_PATTERN}/header_photo"
+    pattern = USER_PATTERN + r"/header_photo"
     example = "https://x.com/USER/header_photo"
 
     def tweets(self):
@@ -1990,10 +1990,10 @@ class TwitterAPI():
                             extr.log.info("Retrying API request as guest")
                             continue
                         raise exception.AuthorizationError(
-                            f"{user['screen_name']} blocked your account")
+                            user["screen_name"] + " blocked your account")
                     elif user.get("protected"):
                         raise exception.AuthorizationError(
-                            f"{user['screen_name']}'s Tweets are protected")
+                            user["screen_name"] + "'s Tweets are protected")
 
                 raise exception.AbortExtraction(
                     "Unable to retrieve Tweets from this timeline")
@@ -2042,7 +2042,7 @@ class TwitterAPI():
                     pinned = None
                 elif pinned := extr._user_obj["legacy"].get(
                         "pinned_tweet_ids_str"):
-                    pinned = f"-tweet-{pinned[0]}"
+                    pinned = "-tweet-" + pinned[0]
                     for idx, entry in enumerate(tweets):
                         if entry["entryId"].endswith(pinned):
                             # mark as pinned / set 'pinned = True'
@@ -2248,7 +2248,7 @@ class TwitterAPI():
     def _update_variables_search(self, variables, cursor, tweet):
         try:
             tweet_id = tweet.get("id_str") or tweet["legacy"]["id_str"]
-            max_id = f"max_id:{int(tweet_id)-1}"
+            max_id = "max_id:" + str(int(tweet_id)-1)
 
             query, n = text.re(r"\bmax_id:\d+").subn(
                 max_id, variables["rawQuery"])
diff --git a/gallery_dl/extractor/unsplash.py b/gallery_dl/extractor/unsplash.py
index b77be959..e2023f35 100644
--- a/gallery_dl/extractor/unsplash.py
+++ b/gallery_dl/extractor/unsplash.py
@@ -74,7 +74,7 @@ class UnsplashExtractor(Extractor):
 class UnsplashImageExtractor(UnsplashExtractor):
     """Extractor for a single unsplash photo"""
     subcategory = "image"
-    pattern = rf"{BASE_PATTERN}/photos/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/photos/([^/?#]+)"
     example = "https://unsplash.com/photos/ID"
 
     def photos(self):
@@ -85,7 +85,7 @@ class UnsplashImageExtractor(UnsplashExtractor):
 class UnsplashUserExtractor(UnsplashExtractor):
     """Extractor for all photos of an unsplash user"""
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/@(\w+)/?$"
+    pattern = BASE_PATTERN + r"/@(\w+)/?$"
     example = "https://unsplash.com/@USER"
 
     def photos(self):
@@ -97,7 +97,7 @@ class UnsplashUserExtractor(UnsplashExtractor):
 class UnsplashFavoriteExtractor(UnsplashExtractor):
     """Extractor for all likes of an unsplash user"""
     subcategory = "favorite"
-    pattern = rf"{BASE_PATTERN}/@(\w+)/likes"
+    pattern = BASE_PATTERN + r"/@(\w+)/likes"
     example = "https://unsplash.com/@USER/likes"
 
     def photos(self):
@@ -109,7 +109,7 @@ class UnsplashFavoriteExtractor(UnsplashExtractor):
 class UnsplashCollectionExtractor(UnsplashExtractor):
     """Extractor for an unsplash collection"""
     subcategory = "collection"
-    pattern = rf"{BASE_PATTERN}/collections/([^/?#]+)(?:/([^/?#]+))?"
+    pattern = BASE_PATTERN + r"/collections/([^/?#]+)(?:/([^/?#]+))?"
     example = "https://unsplash.com/collections/12345/TITLE"
 
     def __init__(self, match):
@@ -128,7 +128,7 @@ class UnsplashCollectionExtractor(UnsplashExtractor):
 class UnsplashSearchExtractor(UnsplashExtractor):
     """Extractor for unsplash search results"""
     subcategory = "search"
-    pattern = rf"{BASE_PATTERN}/s/photos/([^/?#]+)(?:\?([^#]+))?"
+    pattern = BASE_PATTERN + r"/s/photos/([^/?#]+)(?:\?([^#]+))?"
     example = "https://unsplash.com/s/photos/QUERY"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/urlshortener.py b/gallery_dl/extractor/urlshortener.py
index 0056d1be..7a9269d0 100644
--- a/gallery_dl/extractor/urlshortener.py
+++ b/gallery_dl/extractor/urlshortener.py
@@ -32,7 +32,7 @@ BASE_PATTERN = UrlshortenerExtractor.update({
 class UrlshortenerLinkExtractor(UrlshortenerExtractor):
     """Extractor for general-purpose URL shorteners"""
     subcategory = "link"
-    pattern = rf"{BASE_PATTERN}(/[^/?#]+)"
+    pattern = BASE_PATTERN + r"(/[^/?#]+)"
     example = "https://bit.ly/abcde"
 
     def items(self):
diff --git a/gallery_dl/extractor/vichan.py b/gallery_dl/extractor/vichan.py
index 86758f3f..4a1c867f 100644
--- a/gallery_dl/extractor/vichan.py
+++ b/gallery_dl/extractor/vichan.py
@@ -39,7 +39,7 @@ class VichanThreadExtractor(VichanExtractor):
     directory_fmt = ("{category}", "{board}", "{thread} {title}")
     filename_fmt = "{time}{num:?-//} {filename}.{extension}"
     archive_fmt = "{board}_{thread}_{tim}"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/res/(\d+)"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/res/(\d+)"
     example = "https://8kun.top/a/res/12345.html"
 
     def items(self):
@@ -93,7 +93,7 @@ class VichanThreadExtractor(VichanExtractor):
 class VichanBoardExtractor(VichanExtractor):
     """Extractor for vichan boards"""
     subcategory = "board"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)(?:/index|/catalog|/\d+|/?$)"
+    pattern = BASE_PATTERN + r"/([^/?#]+)(?:/index|/catalog|/\d+|/?$)"
     example = "https://8kun.top/a/"
 
     def items(self):
diff --git a/gallery_dl/extractor/vipergirls.py b/gallery_dl/extractor/vipergirls.py
index 8f6368b9..39817632 100644
--- a/gallery_dl/extractor/vipergirls.py
+++ b/gallery_dl/extractor/vipergirls.py
@@ -94,7 +94,7 @@ class VipergirlsExtractor(Extractor):
     def _login_impl(self, username, password):
         self.log.info("Logging in as %s", username)
 
-        url = f"{self.root}/login.php?do=login"
+        url = self.root + "/login.php?do=login"
         data = {
             "vb_login_username": username,
             "vb_login_password": password,
@@ -124,8 +124,8 @@ class VipergirlsExtractor(Extractor):
 class VipergirlsThreadExtractor(VipergirlsExtractor):
     """Extractor for vipergirls threads"""
     subcategory = "thread"
-    pattern = (rf"{BASE_PATTERN}"
-               rf"/threads/(\d+)(?:-[^/?#]+)?(/page\d+)?(?:$|#|\?(?!p=))")
+    pattern = (BASE_PATTERN +
+               r"/threads/(\d+)(?:-[^/?#]+)?(/page\d+)?(?:$|#|\?(?!p=))")
     example = "https://vipergirls.to/threads/12345-TITLE"
 
     def __init__(self, match):
@@ -140,8 +140,8 @@ class VipergirlsThreadExtractor(VipergirlsExtractor):
 class VipergirlsPostExtractor(VipergirlsExtractor):
     """Extractor for vipergirls posts"""
     subcategory = "post"
-    pattern = (rf"{BASE_PATTERN}"
-               rf"/threads/(\d+)(?:-[^/?#]+)?\?p=\d+[^#]*#post(\d+)")
+    pattern = (BASE_PATTERN +
+               r"/threads/(\d+)(?:-[^/?#]+)?\?p=\d+[^#]*#post(\d+)")
     example = "https://vipergirls.to/threads/12345-TITLE?p=23456#post23456"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/vk.py b/gallery_dl/extractor/vk.py
index e7453fcb..ea422651 100644
--- a/gallery_dl/extractor/vk.py
+++ b/gallery_dl/extractor/vk.py
@@ -101,7 +101,7 @@ class VkExtractor(Extractor):
                 url, method="POST", headers=headers, data=data)
             if response.history and "/challenge.html" in response.url:
                 raise exception.AbortExtraction(
-                    f"HTTP redirect to 'challenge' page:\n{response.url}")
+                    "HTTP redirect to 'challenge' page:\n" + response.url)
 
             payload = response.json()["payload"][1]
             if len(payload) < 4:
@@ -134,7 +134,7 @@ class VkExtractor(Extractor):
 class VkPhotosExtractor(VkExtractor):
     """Extractor for photos from a vk user"""
     subcategory = "photos"
-    pattern = (rf"{BASE_PATTERN}/(?:"
+    pattern = (BASE_PATTERN + r"/(?:"
                r"(?:albums|photos|id)(-?\d+)"
                r"|(?!(?:album|tag|wall)-?\d+_?)([^/?#]+))")
     example = "https://vk.com/id12345"
@@ -184,7 +184,7 @@ class VkAlbumExtractor(VkExtractor):
     """Extractor for a vk album"""
     subcategory = "album"
     directory_fmt = ("{category}", "{user[id]}", "{album[id]}")
-    pattern = rf"{BASE_PATTERN}/album(-?\d+)_(\d+)$"
+    pattern = BASE_PATTERN + r"/album(-?\d+)_(\d+)$"
     example = "https://vk.com/album12345_00"
 
     def photos(self):
@@ -228,7 +228,7 @@ class VkTaggedExtractor(VkExtractor):
     """Extractor for a vk tagged photos"""
     subcategory = "tagged"
     directory_fmt = ("{category}", "{user[id]}", "tags")
-    pattern = rf"{BASE_PATTERN}/tag(-?\d+)$"
+    pattern = BASE_PATTERN + r"/tag(-?\d+)$"
     example = "https://vk.com/tag12345"
 
     def __init__(self, match):
@@ -236,7 +236,7 @@ class VkTaggedExtractor(VkExtractor):
         self.user_id = match[1]
 
     def photos(self):
-        return self._pagination(f"tag{self.user_id}")
+        return self._pagination("tag" + self.user_id)
 
     def metadata(self):
         return {"user": {"id": self.user_id}}
@@ -247,7 +247,7 @@ class VkWallPostExtractor(VkExtractor):
     subcategory = "wall-post"
     directory_fmt = ("{category}", "{user[id]}", "wall")
     filename_fmt = "{wall[id]}_{num}.{extension}"
-    pattern = rf"{BASE_PATTERN}/wall(-?\d+)_(\d+)"
+    pattern = BASE_PATTERN + r"/wall(-?\d+)_(\d+)"
     example = "https://vk.com/wall12345_123"
 
     def photos(self):
diff --git a/gallery_dl/extractor/vsco.py b/gallery_dl/extractor/vsco.py
index b8da813b..6046a78c 100644
--- a/gallery_dl/extractor/vsco.py
+++ b/gallery_dl/extractor/vsco.py
@@ -12,7 +12,7 @@ from .common import Extractor, Message, Dispatch
 from .. import text, util
 
 BASE_PATTERN = r"(?:https?://)?(?:www\.)?vsco\.co"
-USER_PATTERN = rf"{BASE_PATTERN}/([^/?#]+)"
+USER_PATTERN = BASE_PATTERN + r"/([^/?#]+)"
 
 
 class VscoExtractor(Extractor):
@@ -133,7 +133,7 @@ class VscoExtractor(Extractor):
 
 class VscoUserExtractor(Dispatch, VscoExtractor):
     """Extractor for a vsco user profile"""
-    pattern = rf"{USER_PATTERN}/?$"
+    pattern = USER_PATTERN + r"/?$"
     example = "https://vsco.co/USER"
 
     def items(self):
@@ -149,7 +149,7 @@ class VscoUserExtractor(Dispatch, VscoExtractor):
 class VscoGalleryExtractor(VscoExtractor):
     """Extractor for a vsco user's gallery"""
     subcategory = "gallery"
-    pattern = rf"{USER_PATTERN}/(?:gallery|images)"
+    pattern = USER_PATTERN + r"/(?:gallery|images)"
     example = "https://vsco.co/USER/gallery"
 
     def images(self):
@@ -158,7 +158,7 @@ class VscoGalleryExtractor(VscoExtractor):
         tkn = data["users"]["currentUser"]["tkn"]
         sid = str(data["sites"]["siteByUsername"][self.user]["site"]["id"])
 
-        url = f"{self.root}/api/3.0/medias/profile"
+        url = self.root + "/api/3.0/medias/profile"
         params = {
             "site_id"  : sid,
             "limit"    : "14",
@@ -173,7 +173,7 @@ class VscoCollectionExtractor(VscoExtractor):
     subcategory = "collection"
     directory_fmt = ("{category}", "{user}", "collection")
     archive_fmt = "c_{user}_{id}"
-    pattern = rf"{USER_PATTERN}/collection"
+    pattern = USER_PATTERN + r"/collection"
     example = "https://vsco.co/USER/collection/1"
 
     def images(self):
@@ -198,7 +198,7 @@ class VscoSpaceExtractor(VscoExtractor):
     subcategory = "space"
     directory_fmt = ("{category}", "space", "{user}")
     archive_fmt = "s_{user}_{id}"
-    pattern = rf"{BASE_PATTERN}/spaces/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/spaces/([^/?#]+)"
     example = "https://vsco.co/spaces/a1b2c3d4e5f"
 
     def images(self):
@@ -245,7 +245,7 @@ class VscoSpaceExtractor(VscoExtractor):
 class VscoSpacesExtractor(VscoExtractor):
     """Extractor for a vsco.co user's spaces"""
     subcategory = "spaces"
-    pattern = rf"{USER_PATTERN}/spaces"
+    pattern = USER_PATTERN + r"/spaces"
     example = "https://vsco.co/USER/spaces"
 
     def items(self):
@@ -275,7 +275,7 @@ class VscoSpacesExtractor(VscoExtractor):
 class VscoAvatarExtractor(VscoExtractor):
     """Extractor for vsco.co user avatars"""
     subcategory = "avatar"
-    pattern = rf"{USER_PATTERN}/avatar"
+    pattern = USER_PATTERN + r"/avatar"
     example = "https://vsco.co/USER/avatar"
 
     def images(self):
@@ -303,7 +303,7 @@ class VscoAvatarExtractor(VscoExtractor):
 class VscoImageExtractor(VscoExtractor):
     """Extractor for individual images on vsco.co"""
     subcategory = "image"
-    pattern = rf"{USER_PATTERN}/media/([0-9a-fA-F]+)"
+    pattern = USER_PATTERN + r"/media/([0-9a-fA-F]+)"
     example = "https://vsco.co/USER/media/0123456789abcdef"
 
     def images(self):
@@ -316,7 +316,7 @@ class VscoImageExtractor(VscoExtractor):
 class VscoVideoExtractor(VscoExtractor):
     """Extractor for vsco.co videos links"""
     subcategory = "video"
-    pattern = rf"{USER_PATTERN}/video/([^/?#]+)"
+    pattern = USER_PATTERN + r"/video/([^/?#]+)"
     example = "https://vsco.co/USER/video/012345678-9abc-def0"
 
     def images(self):
diff --git a/gallery_dl/extractor/wallhaven.py b/gallery_dl/extractor/wallhaven.py
index 9ea3c364..3025c566 100644
--- a/gallery_dl/extractor/wallhaven.py
+++ b/gallery_dl/extractor/wallhaven.py
@@ -113,7 +113,7 @@ class WallhavenCollectionsExtractor(WallhavenExtractor):
         base = f"{self.root}/user/{self.username}/favorites/"
         for collection in self.api.collections(self.username):
             collection["_extractor"] = WallhavenCollectionExtractor
-            url = f"{base}{collection['id']}"
+            url = base + str(collection["id"])
             yield Message.Queue, url, collection
 
 
diff --git a/gallery_dl/extractor/weasyl.py b/gallery_dl/extractor/weasyl.py
index e718e51b..bc1bc711 100644
--- a/gallery_dl/extractor/weasyl.py
+++ b/gallery_dl/extractor/weasyl.py
@@ -70,7 +70,7 @@ class WeasylExtractor(Extractor):
 
 class WeasylSubmissionExtractor(WeasylExtractor):
     subcategory = "submission"
-    pattern = rf"{BASE_PATTERN}(?:~[\w~-]+/submissions|submission|view)/(\d+)"
+    pattern = BASE_PATTERN + r"(?:~[\w~-]+/submissions|submission|view)/(\d+)"
     example = "https://www.weasyl.com/~USER/submissions/12345/TITLE"
 
     def __init__(self, match):
@@ -86,7 +86,7 @@ class WeasylSubmissionExtractor(WeasylExtractor):
 
 class WeasylSubmissionsExtractor(WeasylExtractor):
     subcategory = "submissions"
-    pattern = rf"{BASE_PATTERN}(?:~|submissions/)([\w~-]+)/?$"
+    pattern = BASE_PATTERN + r"(?:~|submissions/)([\w~-]+)/?$"
     example = "https://www.weasyl.com/submissions/USER"
 
     def __init__(self, match):
@@ -101,7 +101,7 @@ class WeasylSubmissionsExtractor(WeasylExtractor):
 class WeasylFolderExtractor(WeasylExtractor):
     subcategory = "folder"
     directory_fmt = ("{category}", "{owner_login}", "{folder_name}")
-    pattern = rf"{BASE_PATTERN}submissions/([\w~-]+)\?folderid=(\d+)"
+    pattern = BASE_PATTERN + r"submissions/([\w~-]+)\?folderid=(\d+)"
     example = "https://www.weasyl.com/submissions/USER?folderid=12345"
 
     def __init__(self, match):
@@ -122,7 +122,7 @@ class WeasylJournalExtractor(WeasylExtractor):
     subcategory = "journal"
     filename_fmt = "{journalid} {title}.{extension}"
     archive_fmt = "{journalid}"
-    pattern = rf"{BASE_PATTERN}journal/(\d+)"
+    pattern = BASE_PATTERN + r"journal/(\d+)"
     example = "https://www.weasyl.com/journal/12345"
 
     def __init__(self, match):
@@ -139,7 +139,7 @@ class WeasylJournalsExtractor(WeasylExtractor):
     subcategory = "journals"
     filename_fmt = "{journalid} {title}.{extension}"
     archive_fmt = "{journalid}"
-    pattern = rf"{BASE_PATTERN}journals/([\w~-]+)"
+    pattern = BASE_PATTERN + r"journals/([\w~-]+)"
     example = "https://www.weasyl.com/journals/USER"
 
     def __init__(self, match):
@@ -159,7 +159,7 @@ class WeasylJournalsExtractor(WeasylExtractor):
 class WeasylFavoriteExtractor(WeasylExtractor):
     subcategory = "favorite"
     directory_fmt = ("{category}", "{user}", "Favorites")
-    pattern = rf"{BASE_PATTERN}favorites(?:\?userid=(\d+)|/([^/?#]+))"
+    pattern = BASE_PATTERN + r"favorites(?:\?userid=(\d+)|/([^/?#]+))"
     example = "https://www.weasyl.com/favorites?userid=12345"
 
     def items(self):
diff --git a/gallery_dl/extractor/webtoons.py b/gallery_dl/extractor/webtoons.py
index bed251b0..a663319f 100644
--- a/gallery_dl/extractor/webtoons.py
+++ b/gallery_dl/extractor/webtoons.py
@@ -48,7 +48,7 @@ class WebtoonsBase():
 class WebtoonsEpisodeExtractor(WebtoonsBase, GalleryExtractor):
     """Extractor for an episode on webtoons.com"""
     subcategory = "episode"
-    pattern = (rf"{LANG_PATTERN}/([^/?#]+)/([^/?#]+)/[^/?#]+)"
+    pattern = (LANG_PATTERN + r"/([^/?#]+)/([^/?#]+)/[^/?#]+)"
                r"/viewer\?([^#'\"]+)")
     example = ("https://www.webtoons.com/en/GENRE/TITLE/NAME/viewer"
                "?title_no=123&episode_no=12345")
@@ -142,7 +142,7 @@ class WebtoonsComicExtractor(WebtoonsBase, Extractor):
     categorytransfer = True
     filename_fmt = "{type}.{extension}"
     archive_fmt = "{title_no}_{type}"
-    pattern = rf"{LANG_PATTERN}/([^/?#]+)/([^/?#]+))/list\?([^#]+)"
+    pattern = LANG_PATTERN + r"/([^/?#]+)/([^/?#]+))/list\?([^#]+)"
     example = "https://www.webtoons.com/en/GENRE/TITLE/list?title_no=123"
 
     def items(self):
@@ -197,7 +197,7 @@ class WebtoonsComicExtractor(WebtoonsBase, Extractor):
 class WebtoonsArtistExtractor(WebtoonsBase, Extractor):
     """Extractor for webtoons.com artists"""
     subcategory = "artist"
-    pattern = rf"{BASE_PATTERN}/p/community/([^/?#]+)/u/([^/?#]+)"
+    pattern = BASE_PATTERN + r"/p/community/([^/?#]+)/u/([^/?#]+)"
     example = "https://www.webtoons.com/p/community/LANG/u/ARTIST"
 
     def items(self):
diff --git a/gallery_dl/extractor/weebcentral.py b/gallery_dl/extractor/weebcentral.py
index 31cdaac9..c5496e32 100644
--- a/gallery_dl/extractor/weebcentral.py
+++ b/gallery_dl/extractor/weebcentral.py
@@ -44,7 +44,7 @@ class WeebcentralBase():
 
 class WeebcentralChapterExtractor(WeebcentralBase, ChapterExtractor):
     """Extractor for manga chapters from weebcentral.com"""
-    pattern = rf"{BASE_PATTERN}(/chapters/(\w+))"
+    pattern = BASE_PATTERN + r"(/chapters/(\w+))"
     example = "https://weebcentral.com/chapters/01JHABCDEFGHIJKLMNOPQRSTUV"
 
     def metadata(self, page):
@@ -95,7 +95,7 @@ class WeebcentralChapterExtractor(WeebcentralBase, ChapterExtractor):
 class WeebcentralMangaExtractor(WeebcentralBase, MangaExtractor):
     """Extractor for manga from weebcentral.com"""
     chapterclass = WeebcentralChapterExtractor
-    pattern = rf"{BASE_PATTERN}/series/(\w+)"
+    pattern = BASE_PATTERN + r"/series/(\w+)"
     example = "https://weebcentral.com/series/01J7ABCDEFGHIJKLMNOPQRSTUV/TITLE"
 
     def chapters(self, _):
diff --git a/gallery_dl/extractor/weibo.py b/gallery_dl/extractor/weibo.py
index abec0f76..c7217d5d 100644
--- a/gallery_dl/extractor/weibo.py
+++ b/gallery_dl/extractor/weibo.py
@@ -14,7 +14,7 @@ from ..cache import cache
 import random
 
 BASE_PATTERN = r"(?:https?://)?(?:www\.|m\.)?weibo\.c(?:om|n)"
-USER_PATTERN = rf"{BASE_PATTERN}/(?:(u|n|p(?:rofile)?)/)?([^/?#]+)(?:/home)?"
+USER_PATTERN = BASE_PATTERN + r"/(?:(u|n|p(?:rofile)?)/)?([^/?#]+)(?:/home)?"
 
 
 class WeiboExtractor(Extractor):
@@ -114,13 +114,13 @@ class WeiboExtractor(Extractor):
                 if not url:
                     continue
                 if url.startswith("http:"):
-                    url = f"https:{url[5:]}"
+                    url = "https:" + url[5:]
                 if "filename" not in file:
                     text.nameext_from_url(url, file)
                     if file["extension"] == "json":
                         file["extension"] = "mp4"
                 if file["extension"] == "m3u8":
-                    url = f"ytdl:{url}"
+                    url = "ytdl:" + url
                     file["_ytdl_manifest"] = "hls"
                     file["extension"] = "mp4"
                 num += 1
@@ -296,7 +296,7 @@ class WeiboExtractor(Extractor):
 class WeiboUserExtractor(WeiboExtractor):
     """Extractor for weibo user profiles"""
     subcategory = "user"
-    pattern = rf"{USER_PATTERN}(?:$|#)"
+    pattern = USER_PATTERN + r"(?:$|#)"
     example = "https://weibo.com/USER"
 
     # do NOT override 'initialize()'
@@ -307,18 +307,18 @@ class WeiboUserExtractor(WeiboExtractor):
     def items(self):
         base = f"{self.root}/u/{self._user_id()}?tabtype="
         return Dispatch._dispatch_extractors(self, (
-            (WeiboHomeExtractor    , f"{base}home"),
-            (WeiboFeedExtractor    , f"{base}feed"),
-            (WeiboVideosExtractor  , f"{base}video"),
-            (WeiboNewvideoExtractor, f"{base}newVideo"),
-            (WeiboAlbumExtractor   , f"{base}album"),
+            (WeiboHomeExtractor    , base + "home"),
+            (WeiboFeedExtractor    , base + "feed"),
+            (WeiboVideosExtractor  , base + "video"),
+            (WeiboNewvideoExtractor, base + "newVideo"),
+            (WeiboAlbumExtractor   , base + "album"),
         ), ("feed",))
 
 
 class WeiboHomeExtractor(WeiboExtractor):
     """Extractor for weibo 'home' listings"""
     subcategory = "home"
-    pattern = rf"{USER_PATTERN}\?tabtype=home"
+    pattern = USER_PATTERN + r"\?tabtype=home"
     example = "https://weibo.com/USER?tabtype=home"
 
     def statuses(self):
@@ -330,7 +330,7 @@ class WeiboHomeExtractor(WeiboExtractor):
 class WeiboFeedExtractor(WeiboExtractor):
     """Extractor for weibo user feeds"""
     subcategory = "feed"
-    pattern = rf"{USER_PATTERN}\?tabtype=feed"
+    pattern = USER_PATTERN + r"\?tabtype=feed"
     example = "https://weibo.com/USER?tabtype=feed"
 
     def statuses(self):
@@ -344,7 +344,7 @@ class WeiboFeedExtractor(WeiboExtractor):
 class WeiboVideosExtractor(WeiboExtractor):
     """Extractor for weibo 'video' listings"""
     subcategory = "videos"
-    pattern = rf"{USER_PATTERN}\?tabtype=video"
+    pattern = USER_PATTERN + r"\?tabtype=video"
     example = "https://weibo.com/USER?tabtype=video"
 
     def statuses(self):
@@ -358,7 +358,7 @@ class WeiboVideosExtractor(WeiboExtractor):
 class WeiboNewvideoExtractor(WeiboExtractor):
     """Extractor for weibo 'newVideo' listings"""
     subcategory = "newvideo"
-    pattern = rf"{USER_PATTERN}\?tabtype=newVideo"
+    pattern = USER_PATTERN + r"\?tabtype=newVideo"
     example = "https://weibo.com/USER?tabtype=newVideo"
 
     def statuses(self):
@@ -370,7 +370,7 @@ class WeiboNewvideoExtractor(WeiboExtractor):
 class WeiboArticleExtractor(WeiboExtractor):
     """Extractor for weibo 'article' listings"""
     subcategory = "article"
-    pattern = rf"{USER_PATTERN}\?tabtype=article"
+    pattern = USER_PATTERN + r"\?tabtype=article"
     example = "https://weibo.com/USER?tabtype=article"
 
     def statuses(self):
@@ -382,7 +382,7 @@ class WeiboArticleExtractor(WeiboExtractor):
 class WeiboAlbumExtractor(WeiboExtractor):
     """Extractor for weibo 'album' listings"""
     subcategory = "album"
-    pattern = rf"{USER_PATTERN}\?tabtype=album"
+    pattern = USER_PATTERN + r"\?tabtype=album"
     example = "https://weibo.com/USER?tabtype=album"
 
     def statuses(self):
@@ -404,7 +404,7 @@ class WeiboAlbumExtractor(WeiboExtractor):
 class WeiboStatusExtractor(WeiboExtractor):
     """Extractor for a weibo status"""
     subcategory = "status"
-    pattern = rf"{BASE_PATTERN}/(detail|status|\d+)/(\w+)"
+    pattern = BASE_PATTERN + r"/(detail|status|\d+)/(\w+)"
     example = "https://weibo.com/detail/12345"
 
     def statuses(self):
diff --git a/gallery_dl/extractor/wikiart.py b/gallery_dl/extractor/wikiart.py
index 8f3a1c98..edbdf44f 100644
--- a/gallery_dl/extractor/wikiart.py
+++ b/gallery_dl/extractor/wikiart.py
@@ -68,7 +68,7 @@ class WikiartArtistExtractor(WikiartExtractor):
     """Extractor for an artist's paintings on wikiart.org"""
     subcategory = "artist"
     directory_fmt = ("{category}", "{artist[artistName]}")
-    pattern = rf"{BASE_PATTERN}/(?!\w+-by-)([\w-]+)/?$"
+    pattern = BASE_PATTERN + r"/(?!\w+-by-)([\w-]+)/?$"
     example = "https://www.wikiart.org/en/ARTIST"
 
     def __init__(self, match):
@@ -89,7 +89,7 @@ class WikiartArtistExtractor(WikiartExtractor):
 class WikiartImageExtractor(WikiartArtistExtractor):
     """Extractor for individual paintings on wikiart.org"""
     subcategory = "image"
-    pattern = rf"{BASE_PATTERN}/(?!(?:paintings|artists)-by-)([\w-]+)/([\w-]+)"
+    pattern = BASE_PATTERN + r"/(?!(?:paintings|artists)-by-)([\w-]+)/([\w-]+)"
     example = "https://www.wikiart.org/en/ARTIST/TITLE"
 
     def __init__(self, match):
@@ -109,7 +109,7 @@ class WikiartArtworksExtractor(WikiartExtractor):
     """Extractor for artwork collections on wikiart.org"""
     subcategory = "artworks"
     directory_fmt = ("{category}", "Artworks by {group!c}", "{type}")
-    pattern = rf"{BASE_PATTERN}/paintings-by-([\w-]+)/([\w-]+)"
+    pattern = BASE_PATTERN + r"/paintings-by-([\w-]+)/([\w-]+)"
     example = "https://www.wikiart.org/en/paintings-by-GROUP/TYPE"
 
     def __init__(self, match):
@@ -128,7 +128,7 @@ class WikiartArtworksExtractor(WikiartExtractor):
 class WikiartArtistsExtractor(WikiartExtractor):
     """Extractor for artist collections on wikiart.org"""
     subcategory = "artists"
-    pattern = (rf"{BASE_PATTERN}/artists-by-([\w-]+)/([\w-]+)")
+    pattern = (BASE_PATTERN + r"/artists-by-([\w-]+)/([\w-]+)")
     example = "https://www.wikiart.org/en/artists-by-GROUP/TYPE"
 
     def __init__(self, match):
diff --git a/gallery_dl/extractor/wikimedia.py b/gallery_dl/extractor/wikimedia.py
index 70e42c68..aa19fdb8 100644
--- a/gallery_dl/extractor/wikimedia.py
+++ b/gallery_dl/extractor/wikimedia.py
@@ -47,7 +47,7 @@ class WikimediaExtractor(BaseExtractor):
     def _init(self):
         if api_path := self.config_instance("api-path"):
             if api_path[0] == "/":
-                self.api_url = f"{self.root}{api_path}"
+                self.api_url = self.root + api_path
             else:
                 self.api_url = api_path
         else:
@@ -66,7 +66,7 @@ class WikimediaExtractor(BaseExtractor):
     def _search_api_path(self, root):
         self.log.debug("Probing possible API endpoints")
         for path in ("/api.php", "/w/api.php", "/wiki/api.php"):
-            url = f"{root}{path}"
+            url = root + path
             response = self.request(url, method="HEAD", fatal=None)
             if response.status_code < 400:
                 return url
@@ -122,10 +122,10 @@ class WikimediaExtractor(BaseExtractor):
                 yield Message.Url, image["url"], image
 
         if self.subcategories:
-            base = f"{self.root}/wiki/"
+            base = self.root + "/wiki/"
             params["gcmtype"] = "subcat"
             for subcat in self._pagination(params):
-                url = f"{base}{subcat['title'].replace(' ', '_')}"
+                url = base + subcat["title"].replace(" ", "_")
                 subcat["_extractor"] = WikimediaArticleExtractor
                 yield Message.Queue, url, subcat
 
@@ -236,7 +236,7 @@ class WikimediaArticleExtractor(WikimediaExtractor):
     """Extractor for wikimedia articles"""
     subcategory = "article"
     directory_fmt = ("{category}", "{page}")
-    pattern = rf"{BASE_PATTERN}/(?!static/)([^?#]+)"
+    pattern = BASE_PATTERN + r"/(?!static/)([^?#]+)"
     example = "https://en.wikipedia.org/wiki/TITLE"
 
     def __init__(self, match):
@@ -286,7 +286,7 @@ class WikimediaArticleExtractor(WikimediaExtractor):
 class WikimediaWikiExtractor(WikimediaExtractor):
     """Extractor for all files on a MediaWiki instance"""
     subcategory = "wiki"
-    pattern = rf"{BASE_PATTERN}/?$"
+    pattern = BASE_PATTERN + r"/?$"
     example = "https://en.wikipedia.org/"
 
     def params(self):
diff --git a/gallery_dl/extractor/xasiat.py b/gallery_dl/extractor/xasiat.py
index d4dbea17..0b12f0dd 100644
--- a/gallery_dl/extractor/xasiat.py
+++ b/gallery_dl/extractor/xasiat.py
@@ -52,7 +52,7 @@ class XasiatExtractor(Extractor):
 
 class XasiatAlbumExtractor(XasiatExtractor):
     subcategory = "album"
-    pattern = rf"{BASE_PATTERN}/(\d+)/[^/?#]+)"
+    pattern = BASE_PATTERN + r"/(\d+)/[^/?#]+)"
     example = "https://www.xasiat.com/albums/12345/TITLE/"
 
     def items(self):
@@ -86,17 +86,17 @@ class XasiatAlbumExtractor(XasiatExtractor):
 
 class XasiatTagExtractor(XasiatExtractor):
     subcategory = "tag"
-    pattern = rf"{BASE_PATTERN}/tags/[^/?#]+)"
+    pattern = BASE_PATTERN + r"/tags/[^/?#]+)"
     example = "https://www.xasiat.com/albums/tags/TAG/"
 
 
 class XasiatCategoryExtractor(XasiatExtractor):
     subcategory = "category"
-    pattern = rf"{BASE_PATTERN}/categories/[^/?#]+)"
+    pattern = BASE_PATTERN + r"/categories/[^/?#]+)"
     example = "https://www.xasiat.com/albums/categories/CATEGORY/"
 
 
 class XasiatModelExtractor(XasiatExtractor):
     subcategory = "model"
-    pattern = rf"{BASE_PATTERN}/models/[^/?#]+)"
+    pattern = BASE_PATTERN + r"/models/[^/?#]+)"
     example = "https://www.xasiat.com/albums/models/MODEL/"
diff --git a/gallery_dl/extractor/xenforo.py b/gallery_dl/extractor/xenforo.py
index d8536b01..37dc653a 100644
--- a/gallery_dl/extractor/xenforo.py
+++ b/gallery_dl/extractor/xenforo.py
@@ -118,7 +118,7 @@ class XenforoExtractor(BaseExtractor):
     def _login_impl(self, username, password):
         self.log.info("Logging in as %s", username)
 
-        url = f"{self.root}/login/login"
+        url = self.root + "/login/login"
         page = self.request(url).text
         data = {
             "_xfToken": text.extr(page, 'name="_xfToken" value="', '"'),
@@ -140,10 +140,10 @@ class XenforoExtractor(BaseExtractor):
         }
 
     def _pagination(self, base, pnum=None):
-        base = f"{self.root}{base}"
+        base = self.root + base
 
         if pnum is None:
-            url = f"{base}/"
+            url = base + "/"
             pnum = 1
         else:
             url = f"{base}/page-{pnum}"
@@ -160,7 +160,7 @@ class XenforoExtractor(BaseExtractor):
             url = f"{base}/page-{pnum}"
 
     def _pagination_reverse(self, base, pnum=None):
-        base = f"{self.root}{base}"
+        base = self.root + base
 
         url = f"{base}/page-{'9999' if pnum is None else pnum}"
         with self.request_page(url) as response:
@@ -180,7 +180,7 @@ class XenforoExtractor(BaseExtractor):
             if pnum > 1:
                 url = f"{base}/page-{pnum}"
             elif pnum == 1:
-                url = f"{base}/"
+                url = base + "/"
             else:
                 return
 
@@ -282,8 +282,8 @@ BASE_PATTERN = XenforoExtractor.update({
 
 class XenforoPostExtractor(XenforoExtractor):
     subcategory = "post"
-    pattern = (rf"{BASE_PATTERN}(/(?:index\.php\?)?threads"
-               rf"/[^/?#]+/post-|/posts/)(\d+)")
+    pattern = (BASE_PATTERN + r"(/(?:index\.php\?)?threads"
+               r"/[^/?#]+/post-|/posts/)(\d+)")
     example = "https://simpcity.cr/threads/TITLE.12345/post-54321"
 
     def posts(self):
@@ -303,8 +303,8 @@ class XenforoPostExtractor(XenforoExtractor):
 
 class XenforoThreadExtractor(XenforoExtractor):
     subcategory = "thread"
-    pattern = (rf"{BASE_PATTERN}(/(?:index\.php\?)?threads"
-               rf"/(?:[^/?#]+\.)?\d+)(?:/page-(\d+))?")
+    pattern = (BASE_PATTERN + r"(/(?:index\.php\?)?threads"
+               r"/(?:[^/?#]+\.)?\d+)(?:/page-(\d+))?")
     example = "https://simpcity.cr/threads/TITLE.12345/"
 
     def posts(self):
@@ -332,8 +332,8 @@ class XenforoThreadExtractor(XenforoExtractor):
 
 class XenforoForumExtractor(XenforoExtractor):
     subcategory = "forum"
-    pattern = (rf"{BASE_PATTERN}(/(?:index\.php\?)?forums"
-               rf"/(?:[^/?#]+\.)?[^/?#]+)(?:/page-(\d+))?")
+    pattern = (BASE_PATTERN + r"(/(?:index\.php\?)?forums"
+               r"/(?:[^/?#]+\.)?[^/?#]+)(?:/page-(\d+))?")
     example = "https://simpcity.cr/forums/TITLE.123/"
 
     def items(self):
@@ -345,4 +345,4 @@ class XenforoForumExtractor(XenforoExtractor):
         pnum = self.groups[-1]
         for page in self._pagination(path, pnum):
             for path in extract_threads(page):
-                yield Message.Queue, f"{self.root}{text.unquote(path)}", data
+                yield Message.Queue, self.root + text.unquote(path), data
diff --git a/gallery_dl/extractor/xfolio.py b/gallery_dl/extractor/xfolio.py
index 8caff85b..9a10c552 100644
--- a/gallery_dl/extractor/xfolio.py
+++ b/gallery_dl/extractor/xfolio.py
@@ -45,7 +45,7 @@ class XfolioExtractor(Extractor):
 
 class XfolioWorkExtractor(XfolioExtractor):
     subcategory = "work"
-    pattern = rf"{BASE_PATTERN}/portfolio/([^/?#]+)/works/(\d+)"
+    pattern = BASE_PATTERN + r"/portfolio/([^/?#]+)/works/(\d+)"
     example = "https://xfolio.jp/portfolio/USER/works/12345"
 
     def items(self):
@@ -107,7 +107,7 @@ class XfolioWorkExtractor(XfolioExtractor):
 
 class XfolioUserExtractor(XfolioExtractor):
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/portfolio/([^/?#]+)(?:/works)?/?(?:$|\?|#)"
+    pattern = BASE_PATTERN + r"/portfolio/([^/?#]+)(?:/works)?/?(?:$|\?|#)"
     example = "https://xfolio.jp/portfolio/USER"
 
     def works(self):
@@ -129,7 +129,7 @@ class XfolioUserExtractor(XfolioExtractor):
 
 class XfolioSeriesExtractor(XfolioExtractor):
     subcategory = "series"
-    pattern = rf"{BASE_PATTERN}/portfolio/([^/?#]+)/series/(\d+)"
+    pattern = BASE_PATTERN + r"/portfolio/([^/?#]+)/series/(\d+)"
     example = "https://xfolio.jp/portfolio/USER/series/12345"
 
     def works(self):
diff --git a/gallery_dl/extractor/xhamster.py b/gallery_dl/extractor/xhamster.py
index 64113d3b..2806cd10 100644
--- a/gallery_dl/extractor/xhamster.py
+++ b/gallery_dl/extractor/xhamster.py
@@ -31,7 +31,7 @@ class XhamsterGalleryExtractor(XhamsterExtractor):
                      "{gallery[id]} {gallery[title]}")
     filename_fmt = "{num:>03}_{id}.{extension}"
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}(/photos/gallery/[^/?#]+)"
+    pattern = BASE_PATTERN + r"(/photos/gallery/[^/?#]+)"
     example = "https://xhamster.com/photos/gallery/12345"
 
     def items(self):
@@ -102,7 +102,7 @@ class XhamsterGalleryExtractor(XhamsterExtractor):
 class XhamsterUserExtractor(XhamsterExtractor):
     """Extractor for all galleries of an xhamster user"""
     subcategory = "user"
-    pattern = rf"{BASE_PATTERN}/users/([^/?#]+)(?:/photos)?/?(?:$|[?#])"
+    pattern = BASE_PATTERN + r"/users/([^/?#]+)(?:/photos)?/?(?:$|[?#])"
     example = "https://xhamster.com/users/USER/photos"
 
     def items(self):
diff --git a/gallery_dl/extractor/xvideos.py b/gallery_dl/extractor/xvideos.py
index 1f33eac3..6f64c864 100644
--- a/gallery_dl/extractor/xvideos.py
+++ b/gallery_dl/extractor/xvideos.py
@@ -28,7 +28,7 @@ class XvideosGalleryExtractor(XvideosBase, GalleryExtractor):
                      "{gallery[id]} {gallery[title]}")
     filename_fmt = "{category}_{gallery[id]}_{num:>03}.{extension}"
     archive_fmt = "{gallery[id]}_{num}"
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/photos/(\d+)"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/photos/(\d+)"
     example = "https://www.xvideos.com/profiles/USER/photos/12345"
 
     def __init__(self, match):
@@ -86,7 +86,7 @@ class XvideosUserExtractor(XvideosBase, Extractor):
     """Extractor for user profiles on xvideos.com"""
     subcategory = "user"
     categorytransfer = True
-    pattern = rf"{BASE_PATTERN}/([^/?#]+)/?(?:#.*)?$"
+    pattern = BASE_PATTERN + r"/([^/?#]+)/?(?:#.*)?$"
     example = "https://www.xvideos.com/profiles/USER"
 
     def __init__(self, match):
@@ -117,5 +117,5 @@ class XvideosUserExtractor(XvideosBase, Extractor):
 
         base = f"{self.root}/profiles/{self.user}/photos/"
         for gallery in galleries:
-            url = f"{base}{gallery['id']}"
+            url = base + str(gallery["id"])
             yield Message.Queue, url, gallery
diff --git a/gallery_dl/extractor/yiffverse.py b/gallery_dl/extractor/yiffverse.py
index 65289e2a..f1073ed6 100644
--- a/gallery_dl/extractor/yiffverse.py
+++ b/gallery_dl/extractor/yiffverse.py
@@ -98,7 +98,7 @@ class YiffverseExtractor(BooruExtractor):
 class YiffversePostExtractor(YiffverseExtractor):
     subcategory = "post"
     archive_fmt = "{id}"
-    pattern = rf"{BASE_PATTERN}/post/(\d+)"
+    pattern = BASE_PATTERN + r"/post/(\d+)"
     example = "https://yiffverse.com/post/12345"
 
     def posts(self):
@@ -109,7 +109,7 @@ class YiffversePlaylistExtractor(YiffverseExtractor):
     subcategory = "playlist"
     directory_fmt = ("{category}", "{playlist_id}")
     archive_fmt = "p_{playlist_id}_{id}"
-    pattern = rf"{BASE_PATTERN}/playlist/(\d+)"
+    pattern = BASE_PATTERN + r"/playlist/(\d+)"
     example = "https://yiffverse.com/playlist/12345"
 
     def metadata(self):
@@ -124,7 +124,7 @@ class YiffverseTagExtractor(YiffverseExtractor):
     subcategory = "tag"
     directory_fmt = ("{category}", "{search_tags}")
     archive_fmt = "t_{search_tags}_{id}"
-    pattern = rf"{BASE_PATTERN}/(?:tag/([^/?#]+))?(?:/?\?([^#]+))?(?:$|#)"
+    pattern = BASE_PATTERN + r"/(?:tag/([^/?#]+))?(?:/?\?([^#]+))?(?:$|#)"
     example = "https://yiffverse.com/tag/TAG"
 
     def _init(self):
diff --git a/gallery_dl/extractor/zerochan.py b/gallery_dl/extractor/zerochan.py
index b4bbd5ac..44497cfb 100644
--- a/gallery_dl/extractor/zerochan.py
+++ b/gallery_dl/extractor/zerochan.py
@@ -160,7 +160,7 @@ class ZerochanExtractor(BooruExtractor):
 class ZerochanTagExtractor(ZerochanExtractor):
     subcategory = "tag"
     directory_fmt = ("{category}", "{search_tags}")
-    pattern = rf"{BASE_PATTERN}/(?!\d+$)([^/?#]+)/?(?:\?([^#]+))?"
+    pattern = BASE_PATTERN + r"/(?!\d+$)([^/?#]+)/?(?:\?([^#]+))?"
     example = "https://www.zerochan.net/TAG"
 
     def __init__(self, match):
@@ -286,7 +286,7 @@ class ZerochanTagExtractor(ZerochanExtractor):
 
 class ZerochanImageExtractor(ZerochanExtractor):
     subcategory = "image"
-    pattern = rf"{BASE_PATTERN}/(\d+)"
+    pattern = BASE_PATTERN + r"/(\d+)"
     example = "https://www.zerochan.net/12345"
 
     def posts(self):
diff --git a/scripts/init.py b/scripts/init.py
index d064ed05..0dedceab 100755
--- a/scripts/init.py
+++ b/scripts/init.py
@@ -111,8 +111,8 @@ class {ccat}Extractor(Extractor):
 
 class {ccat}{subcat.capitalize()}Extractor({ccat}Extractor):
     subcategory = "{subcat}"
-    pattern = rf"{{BASE_PATTERN}}/PATH"
-    example = "{args.root}/..."
+    pattern = BASE_PATTERN + r"/PATH"
+    example = "{args.root}/PATH"
 
     def items(self):
         pass
@@ -128,6 +128,7 @@ def generate_extractors_manga(args):
     return f'''\
 from .common import ChapterExtractor, MangaExtractor
 from .. import text
+from ..cache import memcache
 
 {build_base_pattern(args)}
 
@@ -139,8 +140,8 @@ class {ccat}Base():
 
 class {ccat}ChapterExtractor({ccat}Base, ChapterExtractor):
     """Extractor for {cat} manga chapters"""
-    pattern = rf"{{BASE_PATTERN}}/PATH"
-    example = "{args.root}/..."
+    pattern = BASE_PATTERN + r"/PATH"
+    example = "{args.root}/PATH"
 
     def __init__(self, match):
         url = f"{{self.root}}/PATH"
@@ -150,6 +151,7 @@ class {ccat}ChapterExtractor({ccat}Base, ChapterExtractor):
         chapter, sep, minor = chapter.partition(".")
 
         return {{
+            **_manga_info(self, manga_id),
             "manga"   : text.unescape(manga),
             "manga_id": text.parse_int(manga_id),
             "title"   : "",
@@ -171,8 +173,8 @@ class {ccat}ChapterExtractor({ccat}Base, ChapterExtractor):
 class {ccat}MangaExtractor({ccat}Base, MangaExtractor):
     """Extractor for {cat} manga"""
     chapterclass = {ccat}ChapterExtractor
-    pattern = rf"{{BASE_PATTERN}}/PATH"
-    example = "{args.root}/..."
+    pattern = BASE_PATTERN + r"/PATH"
+    example = "{args.root}/PATH"
 
     def __init__(self, match):
         url = f"{{self.root}}/PATH"
@@ -185,6 +187,11 @@ class {ccat}MangaExtractor({ccat}Base, MangaExtractor):
             results.append((url, None))
 
         return results
+
+
+@memcache(keyarg=1)
+def _manga_info(self, slug):
+    return {{}}
 '''
 
 
@@ -197,7 +204,7 @@ from .common import Extractor, Message, Dispatch
 from .. import text
 
 {build_base_pattern(args)}
-USER_PATTERN = rf"{{BASE_PATTERN}}/([^/?#]+)"
+USER_PATTERN = BASE_PATTERN + r"/([^/?#]+)"
 
 class {ccat}Extractor(Extractor):
     """Base class for {cat} extractors"""
@@ -207,13 +214,13 @@ class {ccat}Extractor(Extractor):
 
 class {ccat}UserExtractor(Dispatch, {ccat}Extractor)
     """Extractor for {cat} user profiles"""
-    pattern = rf"{{USER_PATTERN}}/?(?:$|\\?|#)"
+    pattern = USER_PATTERN + r"/?(?:$|\\?|#)"
     example = "{args.root}/USER/"
 
     def items(self):
-        base = f"{{self.root}}/"
+        base = self.root + "/"
         return self._dispatch_extractors((
-            ({ccat}InfoExtractor, f"{{base}}info"),
+            ({ccat}InfoExtractor, base + "info"),
         ), ("posts",))
 '''