def METHOD_NAME(self) -> None:
    """An error should be raised if a bad value is passed in."""
    with self.assertRaises(ConfigError):
        generate_ip_set(("not-an-ip",))
    with self.assertRaises(ConfigError):
        generate_ip_set(("1.2.3.4/128",))
    with self.assertRaises(ConfigError):
        generate_ip_set((":::",))
    # The following get treated as empty data.
    self.assertFalse(generate_ip_set(None))
    self.assertFalse(generate_ip_set({}))