code: def stack_nested_tensors(tensors, axis=0):
      """Stacks a list of nested tensors along the dimension specified.
  
      Args:
        tensors: A list of nested tensors to be stacked.
        axis: the axis along which the stack operation is applied.
  
      Returns:
        A stacked nested tensor.
      """
      return tf.nest.map_structure(
          lambda *tensors: tf.stack(tensors, axis=axis), *tensors
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import collections
  import numbers
  from typing import Optional, Text
  from absl import logging
  import numpy
  from six.moves import zip
  import tensorflow
  from tf_agents.typing import types
  from tf_agents.utils import composite
  import wrapt
  from tensorflow.python.util import nest
label_desc: Use image node_id 20 for calling a global function with example usage: stack_nested_tensors(tensors, axis) and returns: tf