[`typing.NamedTuple`](https://docs.python.org/3/library/typing.html#typing.NamedTuple)
        and
        [`@dataclasses.dataclass`](https://docs.python.org/3/library/dataclasses.html#dataclasses.dataclass)
        from the standard Python library.
    *   Extension types are supported by Keras, tf.data, TF-hub, SavedModel,