Fix linter errors

sublime/adapters/manager.py

@@ -266,12 +266,9 @@ class AdapterManager:
             job.cancel()
 
         AdapterManager.executor.shutdown()
-        print("2")
         AdapterManager.download_executor.shutdown()
-        print("3")
         if AdapterManager._instance:
             AdapterManager._instance.shutdown()
-        print("4")
 
         logging.info("AdapterManager shutdown complete")
 

sublime/app.py

@@ -791,12 +791,13 @@ class SublimeMusicApp(Gtk.Application):
         )
 
         # If already playing, then make the player itself seek.
-        if self.player.song_loaded:
+        if self.player and self.player.song_loaded:
             self.player.seek(new_time)
 
         self.save_play_queue()
 
     def on_device_update(self, win: Any, device_uuid: str):
+        assert self.player
         if device_uuid == self.app_config.state.current_device:
             return
         self.app_config.state.current_device = device_uuid
@@ -997,6 +998,7 @@ class SublimeMusicApp(Gtk.Application):
         # in the callback.
         @dbus_propagate(self)
         def do_play_song(order_token: int, song: Song):
+            assert self.player
             if order_token != self.song_playing_order_token:
                 return