code: def _test_cases(prefix=""):
      return [
          {
              "testcase_name": "%s0" % prefix,
              "network_cls": DummyActorNet,
          },
          {
              "testcase_name": "%s1" % prefix,
              "network_cls": DummyActorDistributionNet,
          },
      ]
  
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 2 for calling a global function with example usage: _test_cases(prefix) and returns: list