code: def testBanditEnvironment(self):
      def _context_sampling_fn():
          return np.array([[5, -5], [2, -2]])
  
      reward_fns = [
          environment_utilities.LinearNormalReward(theta, sigma=0.0)
          for theta in ([1, 0], [0, 1])
      ]
      batch_size = 2
      py_env = sspe.StationaryStochasticPyEnvironment(
          _context_sampling_fn, reward_fns, batch_size=batch_size
      )
      env = tf_py_environment.TFPyEnvironment(py_env)
      policy = random_tf_policy.RandomTFPolicy(
          env.time_step_spec(), env.action_spec()
      )
  
      steps_per_loop = 4
      replay_buffer = tf_uniform_replay_buffer.TFUniformReplayBuffer(
          data_spec=policy.trajectory_spec,
          batch_size=batch_size,
          max_length=steps_per_loop,
      )
  
      driver = dynamic_episode_driver.DynamicEpisodeDriver(
          env,
          policy,
          num_episodes=steps_per_loop * batch_size,
          observers=[replay_buffer.add_batch],
      )
  
      run_driver = driver.run()
      rb_gather_all = replay_buffer.gather_all()
  
      self.evaluate(tf.compat.v1.global_variables_initializer())
      self.evaluate(run_driver)
      trajectories = self.evaluate(rb_gather_all)
  
      self.assertAllEqual(
          trajectories.step_type, [[0, 0, 0, 0], [0, 0, 0, 0]]
      )
      self.assertAllEqual(
          trajectories.next_step_type, [[2, 2, 2, 2], [2, 2, 2, 2]]
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import numpy
  import tensorflow
  from tf_agents.bandits.environments import environment_utilities
  from tf_agents.bandits.environments import stationary_stochastic_py_environment
  from tf_agents.drivers import dynamic_episode_driver
  from tf_agents.drivers import test_utils
  from tf_agents.environments import tf_py_environment
  from tf_agents.policies import random_tf_policy
  from tf_agents.replay_buffers import tf_uniform_replay_buffer
  from tf_agents.utils import test_utils
label_desc: Use image node_id 8 for calling the DynamicEpisodeDriverTest obj's underlying member method code with example usage: obj.testBanditEnvironment() and returns: np