code: def tearDownClass(cls) -> None:
      ray.shutdown()
  
imports: import tempfile
  import os
  from pathlib import Path
  import unittest
  import pytest
  import ray
  from ray.rllib.algorithms.algorithm_config import AlgorithmConfig
  from ray.rllib.offline import IOContext
  from ray.rllib.offline.dataset_reader import DatasetReader, get_dataset_and_shards, _unzip_if_needed
label_desc: Use image node_id 2 for calling the TestDatasetReader obj's underlying member method code with example usage: obj.tearDownClass(cls) without return types