How to use the pyscroll.animation.AnimationToken function in pyscroll

self._tracked_gids.add(gid)

            frames = list()
            for frame_gid, frame_duration in frame_data:
                image = self._get_tile_image_by_id(frame_gid)
                frames.append(AnimationFrame(image, frame_duration))

            # the following line is slow when loading maps, but avoids overhead when rendering
            # positions = set(self.tmx.get_tile_locations_by_gid(gid))

            # ideally, positions would be populated with all the known
            # locations of an animation, but searching for their locations
            # is slow. so it will be updated as the map is drawn.

            positions = set()
            ani = AnimationToken(positions, frames, self._last_time)
            self._animation_map[gid] = ani
            heappush(self._animation_queue, ani)