code: def tearDownClass(cls) -> None:
      ray.shutdown()
  
file_path: ray/python/ray/rllib/algorithms/impala/tests/test_impala.py
imports: import unittest
  import ray
  import ray.rllib.algorithms.impala
  from ray.rllib.policy.sample_batch import DEFAULT_POLICY_ID
  from ray.rllib.utils.framework import try_import_tf
  from ray.rllib.utils.metrics.learner_info import LEARNER_INFO, LEARNER_STATS_KEY
  from ray.rllib.utils.test_utils import check, check_compute_single_action, check_train_results, framework_iterator
label_desc: Use image node_id 2 for calling the TestIMPALA obj's underlying member method code with example usage: obj.tearDownClass(cls) without return types