code: def edges_touching_tile(tile_id):
      
      coord = tile_id_to_coord(tile_id)
      edges = []
      for offset in _tile_edge_offsets.keys():
          edges.append(coord + offset)
      # logging.debug('tile_id={}, edges touching={}'.format(tile_id, edges))
      return edges
docs: Get a list of edge coordinates touching the given tile.
  
      :param tile_id: tile identifier, Tile.tile_id
      :return: list of edge coordinates touching the given tile, list(int)