[webtoons] small optimization

don't extract the entire 'author_area' and
avoid creating a second 'text.extract_from()' object

gallery_dl/extractor/webtoons.py

@@ -92,10 +92,11 @@ class WebtoonsEpisodeExtractor(WebtoonsBase, GalleryExtractor):
         title = extr('<meta property="og:title" content="', '"')
         descr = extr('<meta property="og:description" content="', '"')
 
-        author_area = extr('<div class="author_area">', '</div>')
-        aa_extr = text.extract_from(author_area)
-        username = aa_extr('/creator/', '"')
-        author_name = aa_extr('<span>', '</span>')
+        if extr('<div class="author_area"', '\n'):
+            username = extr('/creator/', '"')
+            author_name = extr('<span>', '</span>')
+        else:
+            username = author_name = ""
 
         return {
             "genre"       : self.genre,

test/results/webtoons.py

@@ -20,6 +20,22 @@ __tests__ = (
         "42055e44659f6ffc410b3fb6557346dfbb993df3",
         "49e1f2def04c6f7a6a3dacf245a1cd9abe77a6a9",
     ],
+
+    "author_name" : "Chris McCoy",
+    "comic"       : "safely-endangered",
+    "comic_name"  : "Safely Endangered",
+    "count"       : 5,
+    "description" : "Silly comics for silly people.",
+    "episode"     : "572",
+    "episode_name": "Ep. 572 - Earth",
+    "episode_no"  : "572",
+    "genre"       : "comedy",
+    "lang"        : "en",
+    "language"    : "English",
+    "num"         : range(1, 5),
+    "title"       : "Safely Endangered - Ep. 572 - Earth",
+    "title_no"    : "352",
+    "username"    : "safelyendangered",
 },
 
 {