code: def previous_song(self):
          
          if self.current_song is None:
              return self._get_good_song(base=-1, direction=-1)
  
          if self.playback_mode == PlaybackMode.random:
              previous_song = self._get_good_song(direction=-1)
          else:
              current_index = self._songs.index(self.current_song)
              previous_song = self._get_good_song(base=current_index - 1, direction=-1)
          return previous_song
docs: previous song for player to play
  
          NOTE: not the last played song