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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def previous_song(self):
 """previous song for player to play NOTE: not the last played song """

        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