code: def decay(epoch):
      if epoch < 3:
          return 1e-3
      elif epoch >= 3 and epoch < 7:
          return 1e-4
      else:
          return 1e-5
  
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 2 for calling a global function with example usage: decay(epoch) and returns: int, int, int