def get_tracks(self):
        """
        Retrieves all the tracks of the album if they haven't been retrieved yet
        :return: List. Tracks of the current album
        """
        if not self._track_list:
            tracks = itunespy.lookup(id=self.collection_id, entity=itunespy.entities['song'])[1:]
            for track in tracks:
                self._track_list.append(track)
        return self._track_list