code: def test_dataset_with_preprocess(self):
      def validate_data_observer(traj):
          if not array_spec.check_arrays_nest(
              traj, self._array_data_spec
          ):
              raise ValueError(
                  "Trajectory incompatible with array_data_spec"
              )
  
      def preprocess(traj):
          episode, step = traj.observation
          return traj.replace(observation=(episode, step + 1))
  
      # Observe 10 steps from the env.  This isn't the num_steps we're testing.
      self._insert_random_data(
          self._env,
          num_steps=10,
          additional_observers=[validate_data_observer],
          sequence_length=4,
      )
  
      replay = reverb_replay_buffer.ReverbReplayBuffer(
          self._data_spec,
          self._table_name,
          local_server=self._server,
          sequence_length=4,
      )
  
      dataset = replay.as_dataset(num_steps=2)
      for sample, _ in dataset.take(5):
          episode, step = sample.observation
          self.assertEqual(episode[0], episode[1])
          self.assertEqual(step[0] + 1, step[1])
          # From even to odd steps
          self.assertEqual(0, step[0].numpy() % 2)
          self.assertEqual(1, step[1].numpy() % 2)
  
      dataset = replay.as_dataset(
          num_steps=2,
          sample_batch_size=1,
          sequence_preprocess_fn=preprocess,
      )
      for sample, _ in dataset.take(5):
          episode, step = sample.observation
          self.assertEqual(episode[0, 0], episode[0, 1])
          self.assertEqual(step[0, 0] + 1, step[0, 1])
          # Makes sure the preprocess has happened.
          # From odd to even steps
          self.assertEqual(1, step[0, 0].numpy() % 2)
          self.assertEqual(0, step[0, 1].numpy() % 2)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import parameterized
  import reverb
  import tensorflow
  from tf_agents.drivers import py_driver
  from tf_agents.environments import test_envs
  from tf_agents.policies import random_py_policy
  from tf_agents.replay_buffers import reverb_replay_buffer
  from tf_agents.replay_buffers import reverb_utils
  from tf_agents.specs import array_spec
  from tf_agents.specs import tensor_spec
  from tf_agents.trajectories import trajectory
  from tf_agents.utils import common
  from tf_agents.utils import test_utils
label_desc: Use image node_id 6 for calling the ReverbReplayBufferTest obj's underlying member method code with example usage: obj.test_dataset_with_preprocess() and returns: traj