class_docstr: Callback for printing the LR at the end of each epoch.
docstr: Implements on_epoch_end() callback.
code: def on_epoch_end(self, epoch, logs=None):
      """Implements on_epoch_end() callback."""
      print(
          "\nLearning rate for epoch {} is {}".format(
              epoch + 1, model.optimizer.lr.numpy()
          )
      )
  
file_path: cloud/src/python/tensorflow_cloud/core/tests/testdata/mnist_example_using_fit.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import tensorflow
  import tensorflow_datasets
label_desc: Use image node_id 1 for calling the PrintLR obj's underlying member method code with example usage: obj.on_epoch_end(epoch, logs) without return types