code: def one_batch(self):
      if self.n is not None and len(self) == 0:
          raise ValueError(
              f"This DataLoader does not contain any batches"
          )
      with self.fake_l.no_multiproc():
          res = first(self)
      if hasattr(self, "it"):
          delattr(self, "it")
      return res
  
imports: from __future__ import annotations
  from ..torch_basics import *
  from torch.utils.data.dataloader import _MultiProcessingDataLoaderIter, _SingleProcessDataLoaderIter, _DatasetKind
label_desc: Use image node_id 20 for calling the DataLoader obj's underlying member method code with example usage: obj.one_batch() and returns: res