code: def testDistributionNotImplemented(self):
      policy = PolicyNoDistribution()
  
      with self.assertRaisesRegex(
          NotImplementedError, "_distribution has not been implemented"
      ):
          policy.distribution(
              ts.TimeStep(
                  step_type=(), reward=(), discount=(), observation=()
              )
          )
  
      train_step = common.create_variable("train_step", initial_value=0)
      saver = policy_saver.PolicySaver(
          policy, train_step=train_step, batch_size=None
      )
      path = os.path.join(self.get_temp_dir(), "save_model")
  
      self.evaluate(tf.compat.v1.global_variables_initializer())
      with self.cached_session():
          saver.save(path)
  
      reloaded = tf.compat.v2.saved_model.load(path)
      with self.assertRaisesRegex(
          tf.errors.InvalidArgumentError,
          "_distribution has not been implemented",
      ):
          reloaded.distribution(
              ts.TimeStep(
                  step_type=(), reward=(), discount=(), observation=()
              )
          )
          # Latest op in graph is the call op for fn so evaluate it.
          self.evaluate(
              tf.compat.v1.get_default_graph().get_operations()[-1]
          )
  
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 15 for calling the PolicySaverTest obj's underlying member method code with example usage: obj.testDistributionNotImplemented() without return types