code: def test_correctness_single_state_stack(self):
      sequence = np.arange(24).reshape((2, 3, 4)).astype("float32")
      layer = layers.RNN([OneStateRNNCell(3), OneStateRNNCell(2)])
      output = layer(sequence)
      self.assertAllClose(
          np.array([[786.0, 786.0], [4386.0, 4386.0]]), output
      )
  
      layer = layers.RNN(
          [OneStateRNNCell(3), OneStateRNNCell(2)],
          return_sequences=True,
      )
      output = layer(sequence)
      self.assertAllClose(
          np.array(
              [
                  [[18.0, 18.0], [156.0, 156.0], [786.0, 786.0]],
                  [[162.0, 162.0], [1020.0, 1020.0], [4386.0, 4386.0]],
              ]
          ),
          output,
      )
  
      layer = layers.RNN(
          [OneStateRNNCell(3), OneStateRNNCell(2)], return_state=True
      )
      output, state_1, state_2 = layer(sequence)
      self.assertAllClose(
          np.array([[786.0, 786.0], [4386.0, 4386.0]]), output
      )
      self.assertAllClose(
          np.array([[158.0, 158.0, 158.0], [782.0, 782.0, 782.0]]),
          state_1,
      )
      self.assertAllClose(
          np.array([[786.0, 786.0], [4386.0, 4386.0]]), state_2
      )
  
      layer = layers.RNN(
          [OneStateRNNCell(3), OneStateRNNCell(2)],
          return_sequences=True,
          return_state=True,
      )
      output, state_1, state_2 = layer(sequence)
      self.assertAllClose(
          np.array(
              [
                  [[18.0, 18.0], [156.0, 156.0], [786.0, 786.0]],
                  [[162.0, 162.0], [1020.0, 1020.0], [4386.0, 4386.0]],
              ]
          ),
          output,
      )
      self.assertAllClose(
          np.array([[158.0, 158.0, 158.0], [782.0, 782.0, 782.0]]),
          state_1,
      )
      self.assertAllClose(
          np.array([[786.0, 786.0], [4386.0, 4386.0]]), state_2
      )
  
file_path: keras/keras/layers/rnn/stacked_rnn_cells_test.py
imports: import numpy
  import pytest
  from keras import layers
  from keras import testing
  from keras.layers.rnn.rnn_test import OneStateRNNCell
  from keras.layers.rnn.rnn_test import TwoStatesRNNCell
label_desc: Use image node_id 2 for calling the StackedRNNTest obj's underlying member method code with example usage: obj.test_correctness_single_state_stack() without return types