code: def get_iterator(self, split, *args, **kwargs):
      if split == "train":
          if self.dataset in ["ptb", "wt2", "wt103", "enwik8", "text8"]:
              data_iter = LMOrderedIterator(self.train, *args, **kwargs)
          elif self.dataset == "lm1b":
              kwargs["shuffle"] = True
              data_iter = LMMultiFileIterator(
                  self.train, self.vocab, *args, **kwargs
              )
      elif split in ["valid", "test"]:
          data = self.valid if split == "valid" else self.test
          if self.dataset in ["ptb", "wt2", "wt103", "enwik8", "text8"]:
              data_iter = LMOrderedIterator(data, *args, **kwargs)
          elif self.dataset == "lm1b":
              data_iter = LMShuffledIterator(data, *args, **kwargs)
      else:
          data_iter = None
          raise ValueError(f"Split not recognized: {split}")
  
      return data_iter
  
imports: import glob
  import os
  import pickle
  import re
  from collections import Counter, OrderedDict
  from typing import List, Optional, Tuple
  import numpy
  from ...tokenization_utils import PreTrainedTokenizer
  from ...utils import cached_file, is_sacremoses_available, is_torch_available, logging, requires_backends, torch_only_method
label_desc: Use image node_id 4 for calling the TransfoXLCorpus obj's underlying member method code with example usage: obj.get_iterator(split) and returns: data_iter