code: def max_pool_2x2(x):
      """max_pool_2x2 downsamples a feature map by 2X."""
      return tf.nn.max_pool(
          x, ksize=[1, 2, 2, 1], strides=[1, 2, 2, 1], padding="SAME"
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import time
  import tensorflow
  from tensorflow.examples.tutorials.mnist import input_data
  import ray
  import ray.experimental.tf_utils
  from bigdl.dllib.utils.log4Error import invalidInputError
label_desc: Use image node_id 4 for calling a global function with example usage: max_pool_2x2(x) and returns: tf