def METHOD_NAME(self):
    """Tests that custom_tiles["wms"] is a dict w/ expected keys/values."""
    tiles = custom_tiles["wms"]
    self.assertIsInstance(tiles, dict)
    for _, value in tiles.items():
        self.assertIsInstance(value["url"], str)
        self.assertIsInstance(value["attribution"], str)
        self.assertIsInstance(value["name"], str)
        self.assertTrue(value["url"].startswith("http"))