code: def testValidateOk(self):
      env = get_mock_env(
          self._action_spec, self._observation_spec, None
      )
      rng = np.random.RandomState()
  
      sample_fn = lambda: array_spec.sample_spec_nest(
          env.observation_spec(), rng
      )
  
      def step(unused_time_step):
          if rng.rand() < 0.10:
              return ts.termination(
                  sample_fn(), 0.0
              )  # pytype: disable=wrong-arg-types
          else:
              return ts.transition(
                  sample_fn(), 1.0
              )  # pytype: disable=wrong-arg-types
  
      env.step = step
      env.reset = lambda: ts.restart(sample_fn())
  
      utils.validate_py_environment(env, episodes=2)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from absl.testing.absltest import mock
  import numpy
  from tf_agents.environments import random_py_environment
  from tf_agents.environments import utils
  from tf_agents.specs import array_spec
  from tf_agents.trajectories import time_step
  from tf_agents.utils import test_utils
label_desc: Use image node_id 2 for calling the UtilsTest obj's underlying member method code with example usage: obj.testValidateOk() and returns: ts, ts