code: def _as_sample_batch(
      batch: Union[SampleBatch, MultiAgentBatch],
      policy_id: PolicyID = DEFAULT_POLICY_ID,
  ) -> SampleBatch:
      """Returns a SampleBatch. If MultiAgentBatch then return the SampleBatch
      corresponding to the given policy_id.
      """
      if type(batch) == SampleBatch:
          return batch
      elif type(batch) == MultiAgentBatch:
          return batch.policy_batches[policy_id]
      else:
          raise NotImplementedError
  
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 6 for calling a global function with example usage: _as_sample_batch(batch, policy_id) and returns: batch, batch