fixing per review comments

beetsplug/discogs.py

@@ -306,7 +306,7 @@ class DiscogsPlugin(BeetsPlugin):
         style = result.data.get('styles')
         if style is None:
             self._log.debug('Style not Found')
-        elif len(style) == 0:
+        elif not style:
             return style
         else:
             style = self.config['separator'].as_str().join(sorted(style))

test/test_discogs.py

@@ -84,7 +84,6 @@ class DGAlbumInfoTest(_common.TestCase):
         tracklist where tracks have the specified `positions`."""
         tracks = [self._make_track('TITLE%s' % i, position) for
                   (i, position) in enumerate(positions, start=1)]
-        release = self._make_release(tracks)
         return self._make_release(tracks)
 
     def test_parse_media_for_tracks(self):