functions. AutoGraph is also applied in functions used with tf.data,
    tf.distribute and tf.keras APIs.
*   Unification of exchange formats to SavedModel. All TensorFlow ecosystem
    projects (TensorFlow Lite, TensorFlow JS, TensorFlow Serving, TensorFlow
    Hub) accept SavedModels. Model state should be saved to and restored from
    SavedModels.
*   API Changes: Many API symbols have been renamed or removed, and argument