code: def test_episodic_observer_update_priority(self):
      observer = reverb_utils.ReverbAddEpisodeObserver(
          self._mock_client,
          table_name="test_table",
          max_sequence_length=1,
          priority=3,
      )
      self.assertEqual(observer._priority, 3)
      observer.update_priority(4)
      self.assertEqual(observer._priority, 4)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import contextlib
  import functools
  import time
  from absl.testing import parameterized
  import mock
  import reverb
  from six.moves import range
  import tensorflow
  from tf_agents.drivers import py_driver
  from tf_agents.environments import parallel_py_environment
  from tf_agents.environments import test_envs
  from tf_agents.policies import random_py_policy
  from tf_agents.replay_buffers import reverb_replay_buffer
  from tf_agents.replay_buffers import reverb_utils
  from tf_agents.specs import tensor_spec
  from tf_agents.system import system_multiprocessing
  from tf_agents.trajectories import time_step
  from tf_agents.utils import test_utils
label_desc: Use image node_id 9 for calling the ReverbObserverTest obj's underlying member method code with example usage: obj.test_episodic_observer_update_priority() without return types