code: def test_dataloader(self):
      dataloader = get_petastorm_dataloader(
          dataset=self.eval_dataset,
          batch_size=self.reader_options.minibatch_size,
          batch_preprocessor=self.batch_preprocessor,
          use_gpu=False,
          reader_options=self.reader_options,
      )
      return self._closing_iter(dataloader)
  
imports: import logging
  from typing import Dict, List, Optional
  import pytorch_lightning
  import torch
  from petastorm import make_batch_reader
  from petastorm.pytorch import DataLoader, decimal_friendly_collate
  from reagent.core.oss_tensorboard_logger import OssTensorboardLogger
  from reagent.data.spark_utils import get_spark_session
  from reagent.preprocessing.batch_preprocessor import BatchPreprocessor
  from reagent.training import StoppingEpochCallback
  from reagent.training.reagent_lightning_module import has_test_step_override
  from .types import Dataset, ReaderOptions, ResourceOptions
label_desc: Use image node_id 4 for calling the PetastormLightningDataModule obj's underlying member method code with example usage: obj.test_dataloader() and returns: self