[8tracks] Modernize

youtube_dl/extractor/eighttracks.py

@@ -103,8 +103,7 @@ class EightTracksIE(InfoExtractor):
     }
 
     def _real_extract(self, url):
-        mobj = re.match(self._VALID_URL, url)
-        playlist_id = mobj.group('id')
+        playlist_id = self._match_id(url)
 
         webpage = self._download_webpage(url, playlist_id)