code: def testTrainStepNotSaved(self):
      if not common.has_eager_been_enabled():
          self.skipTest(
              "Only supported in TF2.x. Step is required in TF1.x"
          )
  
      network = q_network.QNetwork(
          input_tensor_spec=self._time_step_spec.observation,
          action_spec=self._action_spec,
      )
  
      policy = q_policy.QPolicy(
          time_step_spec=self._time_step_spec,
          action_spec=self._action_spec,
          q_network=network,
      )
  
      saver = policy_saver.PolicySaver(policy, batch_size=None)
      path = os.path.join(self.get_temp_dir(), "save_model")
  
      saver.save(path)
      reloaded = tf.compat.v2.saved_model.load(path)
  
      self.assertIn("get_train_step", reloaded.signatures)
      train_step_value = self.evaluate(reloaded.get_train_step())
      self.assertEqual(-1, train_step_value)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import collections
  import os
  import shutil
  from absl.testing import parameterized
  import numpy
  import tensorflow
  import tensorflow_probability
  from tf_agents.networks import actor_distribution_network
  from tf_agents.networks import q_network
  from tf_agents.networks import q_rnn_network
  from tf_agents.policies import actor_policy
  from tf_agents.policies import policy_saver
  from tf_agents.policies import q_policy
  from tf_agents.policies import tf_policy
  from tf_agents.specs import tensor_spec
  from tf_agents.trajectories import policy_step
  from tf_agents.trajectories import time_step
  from tf_agents.utils import common
  from tf_agents.utils import test_utils
label_desc: Use image node_id 12 for calling the PolicySaverTest obj's underlying member method code with example usage: obj.testTrainStepNotSaved() without return types