MaskedTensor(tf.experimental.ExtensionType): values: tf.Tensor mask:
        tf.Tensor` The `tf.ExtensionType` base class works similarly to
        [`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.