def METHOD_NAME(self):
    xs = tf.cast(
        tf.stack(
            [2 * tf.ones((100, 100, 1)), tf.ones((100, 100, 1))], axis=0
        ),
        tf.float32,
    )
    layer = FourierMix()
    with self.assertRaisesRegexp(
        ValueError, "expects inputs in a dictionary"
    ):
        _ = layer(xs)