code: def testVariables(self):
      mock_tf_py_policy = tf_py_policy.TFPyPolicy(
          self._get_mock_py_policy()
      )
      np.testing.assert_equal(mock_tf_py_policy.variables(), [])
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing.absltest import mock
  import numpy
  import tensorflow
  from tf_agents.policies import py_policy
  from tf_agents.policies import random_py_policy
  from tf_agents.policies import tf_py_policy
  from tf_agents.specs import array_spec
  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 nest_utils
  from tf_agents.utils import test_utils
label_desc: Use image node_id 5 for calling the TFPyPolicyTest obj's underlying member method code with example usage: obj.testVariables() without return types