code: def check_destinations(destinations):
      """Checks whether `destinations` is not empty.
  
      Args:
        destinations: a `DistributedValues`, variable, or string object.
  
      Returns:
        Boolean which is True if `destinations` is not empty.
      """
      # Calling bool() on a ResourceVariable is not allowed.
      if isinstance(
          destinations,
          (resource_variable_ops.BaseResourceVariable, ops.Tensor),
      ):
          return bool(destinations.device)
      return bool(destinations)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import collections
  import enum
  import six
  from tensorflow.python.client import device_lib
  from tensorflow.python.distribute import cross_device_utils
  from tensorflow.python.distribute import device_util
  from tensorflow.python.distribute import reduce_util
  from tensorflow.python.distribute import values
  from tensorflow.python.eager import context
  from tensorflow.python.framework import kernels
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import resource_variable_ops
  from tensorflow.python.platform import tf_logging
  from tensorflow.python.util.tf_export import tf_export
  from tensorflow.tools.docs import doc_controls
  import tensorflow
  from tensorflow.python.distribute.cross_device_ops import CollectiveAllReduce
  import tensorflow.python.distribute.cross_device_ops
  from byteps.tensorflow.ops import broadcast, _push_pull
  from byteps.tensorflow import local_rank, size
label_desc: Use image node_id 1 for calling a global function with example usage: check_destinations(destinations) and returns: bool, bool