code: def get_device_str(device_id, num_gpus):
      """Return a device string for multi-GPU setup."""
      if num_gpus == 0:
          return "/cpu:0"
      device_str_output = "/gpu:%d" % (device_id % num_gpus)
      return device_str_output
  
imports: from __future__ import print_function
  import collections
  import os
  import time
  import numpy
  import six
  import tensorflow
  from tensorflow.python.ops import lookup_ops
  from .utils import misc_utils, vocab_utils, iterator_utils
label_desc: Use image node_id 2 for calling a global function with example usage: get_device_str(device_id, num_gpus) and returns: device_str_output, str