code: def default_zone():
      return cloud.shell_output(DEFAULT_ZONE).strip()
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import contextlib
  import multiprocessing
  import os
  import socket
  import subprocess
  import time
  from tensor2tensor.utils import cloud_mlengine
  import tensorflow.compat.v1
label_desc: Use image node_id 2 for calling a global function with example usage: default_zone() and returns: cloud