code: def get_available_gpus():
      """
      Returns a list of string names of all available GPUs
      """
      local_device_protos = device_lib.list_local_devices()
      return [
          x.name for x in local_device_protos if x.device_type == "GPU"
      ]
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from __future__ import unicode_literals
  import logging
  import math
  import os
  import time
  import warnings
  import numpy
  import six
  from six.moves import xrange
  import tensorflow
  from cleverhans.compat import device_lib
  from cleverhans.compat import reduce_sum, reduce_mean
  from cleverhans.compat import reduce_max
  from cleverhans.compat import softmax_cross_entropy_with_logits
  from cleverhans.utils import batch_indices, _ArgsWrapper, create_logger
label_desc: Use image node_id 17 for calling a global function with example usage: get_available_gpus() and returns: unknown