in `early_stopping.py`.

*   `tf.estimator`:

    *   Premade estimators in the tf.estimator.DNN/Linear/DNNLinearCombined
        family have been updated to use `tf.keras.optimizers` instead of the
        `tf.compat.v1.train.Optimizer`s. If you do not pass in an `optimizer=`
        arg or if you use a string, the premade estimator will use the Keras