def previous_track(self, device_id=None):
        """ Skip user's playback to previous track.

            Parameters:
                - device_id - device target for playback
        """
        return self._post(
            self._append_device_id("me/player/previous", device_id)
        )
 Skip user's playback to previous track.

            Parameters:
                - device_id - device target for playback
        
spotipy/client.py