code: def setUpClass(cls):
      ray.init()
  
imports: import unittest
  from typing import List, Union
  import numpy
  from rllib_dt.dt.segmentation_buffer import MultiAgentSegmentationBuffer, SegmentationBuffer
  import ray
  from ray.rllib.policy.sample_batch import DEFAULT_POLICY_ID, MultiAgentBatch, SampleBatch, concat_samples
  from ray.rllib.utils import test_utils
  from ray.rllib.utils.framework import try_import_tf, try_import_torch
  from ray.rllib.utils.typing import PolicyID
label_desc: Use image node_id 1 for calling the TestSegmentationBuffer obj's underlying member method code with example usage: obj.setUpClass(cls) without return types