simplify if statements by using walrus operators (#7671)

gallery_dl/extractor/pixiv.py

@@ -89,8 +89,7 @@ class PixivExtractor(Extractor):
                                          if tag["is_registered"]]
             if self.meta_captions and not work.get("caption") and \
                     not work.get("_mypixiv") and not work.get("_ajax"):
-                body = self._request_ajax("/illust/" + str(work["id"]))
-                if body:
+                if body := self._request_ajax("/illust/" + str(work["id"])):
                     work["caption"] = self._sanitize_ajax_caption(
                         body["illustComment"])
 
@@ -293,8 +292,7 @@ class PixivExtractor(Extractor):
 
     def _extract_ajax_url(self, body):
         try:
-            original = body["urls"]["original"]
-            if original:
+            if original := body["urls"]["original"]:
                 return original
         except Exception:
             pass
@@ -699,8 +697,7 @@ class PixivRankingExtractor(PixivExtractor):
         except KeyError:
             raise exception.AbortExtraction(f"Invalid mode '{mode}'")
 
-        date = query.get("date")
-        if date:
+        if date := query.get("date"):
             if len(date) == 8 and date.isdecimal():
                 date = f"{date[0:4]}-{date[4:6]}-{date[6:8]}"
             else: