Convert a tile coordinate to its corresponding tile identifier.

    :param coord: coordinate of the tile, int
    :return: tile identifier, Tile.tile_id

def tile_id_from_coord(coord):
    """
    Convert a tile coordinate to its corresponding tile identifier.

    :param coord: coordinate of the tile, int
    :return: tile identifier, Tile.tile_id
    """
    for i, c in _tile_id_to_coord.items():
        if c == coord:
            return i
    raise Exception('Tile id lookup failed, coord={} not found in map'.format(hex(coord)))