x.shape.rank == 1: x = tf.expand_dims(x, axis=-1)`. Functional models as
        well as Sequential models built with an explicit input shape are not
        affected.
    *   The methods `Model.to_yaml()` and `keras.models.model_from_yaml` have
        been replaced to raise a `RuntimeError` as they can be abused to cause
        arbitrary code execution. It is recommended to use JSON serialization