code: def testFirstObservationIsPreservedAfterTwoSteps(self):
      tf_env = TFEnvironmentMock()
      time_step = tf_env.current_time_step()
      self.evaluate(tf.compat.v1.global_variables_initializer())
      time_step_np = self.evaluate(time_step)
      self.assertEqual([0], time_step_np.observation)
      time_step = tf_env.step(1)
      with tf.control_dependencies([time_step.step_type]):
          next_time_step = tf_env.step(2)
  
      observation_np, _ = self.evaluate(
          [time_step.observation, next_time_step]
      )
  
      self.assertEqual([1], observation_np)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import tensorflow
  from tf_agents import specs
  from tf_agents.environments import tf_environment
  from tf_agents.trajectories import time_step
  from tf_agents.utils import common
label_desc: Use image node_id 9 for calling the TFEnvironmentTest obj's underlying member method code with example usage: obj.testFirstObservationIsPreservedAfterTwoSteps() without return types