code: def to_placeholder_with_default(default, spec, outer_dims=()):
      """Creates a placeholder from TensorSpec.
  
      Args:
        default: A constant value of output type dtype.
        spec: Instance of TensorSpec
        outer_dims: Optional leading dimensions of the placeholder.
  
      Returns:
        An instance of tf.placeholder.
      """
      ph_shape = list(outer_dims) + spec.shape.as_list()
      return tf.compat.v1.placeholder_with_default(
          default, ph_shape, spec.name
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  from typing import Union
  import numpy
  import tensorflow
  import tensorflow_probability
  from tf_agents.specs import array_spec
  from tf_agents.typing import types
  from google.protobuf import text_format
  from tensorflow.core.protobuf import struct_pb2
  from tensorflow.python.framework import tensor_spec
  from tensorflow.python.saved_model import nested_structure_coder
label_desc: Use image node_id 8 for calling a global function with example usage: to_placeholder_with_default(default, spec, outer_dims) and returns: tf