def METHOD_NAME(self, xtile, ytile, tiles_list):
    """Check that the tiles in tiles_list have appropriate extents."""
    for tile in tiles_list:
        yse, xse = tile
        ystart, yend = yse
        xstart, xend = xse
        self.assertTrue(0 <= xstart < xend, "Tile empty - xcoord: " + repr(tile))
        self.assertTrue(0 <= ystart < yend, "Tile empty - y coord: " + repr(tile))
        self.assertLessEqual(
            xend - xstart, xtile, "Tile too big - x coord: " + repr(tile)
        )
        self.assertLessEqual(
            yend - ystart, ytile, "Tile too big - y coord: " + repr(tile)
        )