code: def testBuild(self, network_cls):
      actor_network = network_cls(self._action_spec)
      value_network = DummyValueNet()
  
      policy = ppo_policy.PPOPolicy(
          self._time_step_spec,
          self._action_spec,
          actor_network=actor_network,
          value_network=value_network,
      )
  
      self.assertEqual(policy.time_step_spec, self._time_step_spec)
      self.assertEqual(policy.action_spec, self._action_spec)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing import parameterized
  import numpy
  import tensorflow
  import tensorflow_probability
  from tf_agents.agents.ppo import ppo_policy
  from tf_agents.networks import actor_distribution_network
  from tf_agents.networks import mask_splitter_network
  from tf_agents.networks import network
  from tf_agents.networks import sequential
  from tf_agents.networks import value_network
  from tf_agents.specs import distribution_spec
  from tf_agents.specs import tensor_spec
  from tf_agents.trajectories import time_step
  from tf_agents.utils import test_utils
label_desc: Use image node_id 4 for calling the PPOPolicyTest obj's underlying member method code with example usage: obj.testBuild(network_cls) without return types