What is this part used for ?

[dangmanhtruong1995]

Hi, I see that in your code there is this part:

early_stopping1 = tf.contrib.estimator.stop_if_no_decrease_hook(
        estimator,
        metric_name='loss_1',
        max_steps_without_decrease=5,
        min_steps=0
    )

    early_stopping2 = tf.contrib.estimator.stop_if_no_decrease_hook(
        estimator,
        metric_name='loss_2',
        max_steps_without_decrease=5,
        min_steps=0
    )

    early_stopping3 = tf.contrib.estimator.stop_if_lower_hook(
        estimator,
        metric_name='loss_1',
        threshold=10,
        eval_dir=None,
        min_steps=0,
        run_every_secs=60,

    run_every_steps=None
)

May I ask what is it used for ? Because I do not see those variables being used anywhere in the code. Thank you very much.