code: def testObservationsContainExtraFields(self):
      action_spec = {"inp": tensor_spec.TensorSpec([1], tf.float32)}
      time_step_spec = ts.time_step_spec(observation_spec=action_spec)
  
      policy = TfPassThroughPolicy(
          time_step_spec, action_spec, clip=True
      )
  
      observation = {
          "inp": tf.constant(1, shape=(1,), dtype=tf.float32),
          "extra": tf.constant(1, shape=(1,), dtype=tf.int32),
      }
  
      time_step = ts.restart(observation)
  
      action = policy.action(time_step).action
      distribution = policy.distribution(time_step).action
      tf.nest.assert_same_structure(action, action_spec)
      tf.nest.assert_same_structure(distribution, action_spec)
      self.assertEqual(1, self.evaluate(action["inp"]))
      self.assertEqual(1, self.evaluate(distribution["inp"].sample()))
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from typing import cast
  from absl.testing import parameterized
  import numpy
  import tensorflow
  import tensorflow_probability
  from tf_agents.policies import tf_policy
  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 common
  from tf_agents.utils import test_utils
label_desc: Use image node_id 3 for calling the TfPolicyTest obj's underlying member method code with example usage: obj.testObservationsContainExtraFields() without return types