fix some mypy errors

feeluown/library/ytdl.py

@@ -48,7 +48,7 @@ def match_rule(self, url, source=''):
     def select_audio(self, url, _: Optional[str] = None, source='') -> Optional[Media]:
         matched_rule = self.match_rule(url, source)
         if matched_rule is None:
-            return
+            return None
         http_proxy = matched_rule.get('http_proxy')
         ytdl_opts = {}
         ytdl_opts.update(self._default_audio_ytdl_opts)
@@ -71,7 +71,7 @@ def select_audio(self, url, _: Optional[str] = None, source='') -> Optional[Medi
     def select_video(self, url, _: Optional[str] = None, source='') -> Optional[Media]:
         matched_rule = self.match_rule(url, source)
         if matched_rule is None:
-            return
+            return None
         http_proxy = matched_rule.get('http_proxy')
         ytdl_opts = {}
         ytdl_opts.update(self._default_video_ytdl_opts)
@@ -91,7 +91,7 @@ def select_video(self, url, _: Optional[str] = None, source='') -> Optional[Medi
                     ):
                         video_candidates.append((f['url'], f['width']))
             if not (audio_candidates and video_candidates):
-                return
+                return None
             audio_candidates = sorted(
                 audio_candidates, key=lambda c: c[1] or 0, reverse=True
             )
@@ -123,5 +123,7 @@ def select_video(self, url, _: Optional[str] = None, source='') -> Optional[Medi
     # print()
 
     media = ytdl.select_video(url, None, 'ytmusic')
+    assert media is not None
+    assert isinstance(media.manifest, VideoAudioManifest)
     print(media.manifest.video_url)
     print(media.manifest.audio_url)

feeluown/player/playlist.py

@@ -468,6 +468,10 @@ def current_song(self) -> Optional[SongModel]:
         """
         return self._current_song
 
+    @current_song.setter
+    def current_song(self, song: Optional[SongModel]):
+        self.set_current_song(song)
+
     @property
     def current_song_mv(self) -> Optional[VideoModel]:
         return self._current_song_mv
@@ -707,10 +711,6 @@ def set_current_model(self, model) -> asyncio.Task:
             self.a_set_current_model, model, name=TASK_SET_CURRENT_MODEL,
         )
 
-    @current_song.setter
-    def current_song(self, song: Optional[SongModel]):
-        self.set_current_song(song)
-
     def set_current_song(self, song):
         """
         .. versionadded:: 3.7.11

setup.cfg

@@ -11,6 +11,9 @@ ignore = E402
 max-line-length = 89
 exclude = feeluown/mpv.py
 
+[mypy]
+disable_error_code = import-untyped
+
 [yapf]
 column_limit = 89
 based_on_style = pep8
@@ -39,3 +42,7 @@ addopts = -q
           --doctest-modules
 [mypy-feeluown.mpv]
 ignore_errors = True
+
+# I don't know how to type hint mixin class which is related to PyQt5.
+[mypy-feeluown.gui.helpers]
+ignore_errors = True