`tf.mixed_precision. experimental.LossScale` in the constructor, and no
        longer has a `LossScale` associated with it. Instead, `Model.compile`
        will automatically wrap the optimizer with a `LossScaleOptimizer` using
        dynamic loss scaling if `Policy.name` is "mixed_float16".
    *   `tf.keras.mixed_precision.LossScaleOptimizer`'s constructor takes in