docs: def edge_coord_in_direction(tile_id, direction):
      """
      Returns the edge coordinate in the given direction at the given tile identifier.
  
      :param tile_id: tile identifier, int
      :param direction: direction, str
      :return: edge coord, int
      """
      tile_coord = tile_id_to_coord(tile_id)
      for edge_coord in edges_touching_tile(tile_id):
          if tile_edge_offset_to_direction(edge_coord - tile_coord) == direction:
              return edge_coord
      raise ValueError('No edge found in direction={} at tile_id={}'.format(
          direction,
          tile_id
      ))