code: def on(self):
          
          assert spotifyconnect._session_instance.player.num_listeners(
              spotifyconnect.PlayerEvent.MUSIC_DELIVERY) == 0
          spotifyconnect._session_instance.player.on(
              spotifyconnect.PlayerEvent.MUSIC_DELIVERY, self._on_music_delivery)
docs: Turn on the alsa_sink sink.
  
          This is done automatically when the sink is instantiated, so you'll
          only need to call this method if you ever call :meth:`off` and want to
          turn the sink back on.