code: def _perturb_fn(batch: np.ndarray, index: int):
      # shuffle the indexth column features
      random_inds = np.random.permutation(batch.shape[0])
      batch[:, index] = batch[random_inds, index]
  
imports: import copy
  import numpy
  import pandas
  from typing import Callable, Dict, Any
  import ray
  from ray.data import Dataset
  from ray.rllib.policy import Policy
  from ray.rllib.policy.sample_batch import SampleBatch, convert_ma_batch_to_sample_batch
  from ray.rllib.utils.annotations import override, DeveloperAPI, ExperimentalAPI
  from ray.rllib.utils.typing import SampleBatchType
  from ray.rllib.offline.offline_evaluator import OfflineEvaluator
label_desc: Use image node_id 1 for calling a global function with example usage: _perturb_fn(batch, index) without return types