code: def prepare_batch(self, batch, *args, **kwargs):
      batch = SampleList(batch)
      return self.mapping[batch.dataset_type].prepare_batch(batch)
  
file_path: mmf/mmf/common/dataset_loader.py
imports: import warnings
  from mmf.common.sample import SampleList
  from mmf.datasets.multi_dataset_loader import MultiDatasetLoader
  from mmf.utils.build import build_multiple_datamodules, build_test_reporter
label_desc: Use image node_id 8 for calling the DatasetLoader obj's underlying member method code with example usage: obj.prepare_batch(batch) and returns: self