code: def input_files(self, dataset_split=problem_lib.DatasetSplit.TRAIN):
      if dataset_split == problem_lib.DatasetSplit.TRAIN:
          return self.train_files
      elif dataset_split == problem_lib.DatasetSplit.EVAL:
          return self.dev_files
      return self.test_files
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import shutil
  from tensor2tensor.data_generators import problem
  from tensor2tensor.data_generators import text_encoder
  from tensor2tensor.data_generators import text_problems
  import tensorflow.compat.v1
  from tensorflow.compat.v1 import estimator
label_desc: Use image node_id 5 for calling the FakeDistributedProblem obj's underlying member method code with example usage: obj.input_files(dataset_split) and returns: self, self, self