code: def call_fake_controller(
      push_values, pop_values, write_values, output_values
  ):
      """Mock a RNN controller from a set of expected outputs.
  
      Args:
        push_values: Expected controller push values.
        pop_values: Expected controller pop values.
        write_values: Expected controller write values.
        output_values: Expected controller output values.
  
      Returns:
        A callable which behaves like the call method of an NeuralStackCell.
      """
  
      def call(
          cell, inputs, prev_read_values, controller_state, batch_size
      ):
          del inputs
          del prev_read_values
          del batch_size
          next_step = tf.constant(0)
          if hasattr(cell, "current_step"):
              next_step = tf.assign_add(
                  cell.current_step, tf.constant(1)
              )
          return neural_stack.NeuralStackControllerInterface(
              push_strengths=tf.slice(
                  tf.constant(push_values),
                  [next_step, 0, 0, 0],
                  [1, -1, -1, -1],
              ),
              pop_strengths=tf.slice(
                  tf.constant(pop_values),
                  [next_step, 0, 0, 0],
                  [1, -1, -1, -1],
              ),
              write_values=tf.slice(
                  tf.constant(write_values),
                  [next_step, 0, 0],
                  [1, -1, -1],
              ),
              outputs=tf.slice(
                  tf.constant(output_values),
                  [next_step, 0, 0],
                  [1, -1, -1],
              ),
              state=controller_state,
          )
  
      return call
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import mock
  import numpy
  from tensor2tensor.layers import modalities
  from tensor2tensor.models.research import neural_stack
  from tensor2tensor.utils import contrib
  import tensorflow.compat.v1
label_desc: Use image node_id 2 for calling a global function with example usage: call_fake_controller(push_values, pop_values, write_values, output_values) and returns: call, neural_stack