code: def pick_unused_port():
      """Helper function to return an unused port."""
      return portpicker.pick_unused_port()
  
file_path: tensorflow-upstream/tensorflow/dtensor/python/tests/multi_client_test_util.py
imports: import os
  import sys
  from absl import flags
  import portpicker
  from tensorflow.dtensor.python.tests import test_backend_util
  from tensorflow.python.platform import test
label_desc: Use image node_id 1 for calling a global function with example usage: pick_unused_port() and returns: portpicker