class_docstr: Problem spec for WMT En-Fr translation.
class_docstr_tok: ["Problem","spec","for","WMT","En-Fr","translation","."]
code: def source_data_files(self, dataset_split):
      train = dataset_split == problem.DatasetSplit.TRAIN
      if self.use_small_dataset:
          datasets = (
              _ENFR_TRAIN_SMALL_DATA if train else _ENFR_TEST_SMALL_DATA
          )
      else:
          datasets = (
              _ENFR_TRAIN_LARGE_DATA if train else _ENFR_TEST_LARGE_DATA
          )
      return datasets
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  from tensor2tensor.data_generators import problem
  from tensor2tensor.data_generators import text_encoder
  from tensor2tensor.data_generators import text_problems
  from tensor2tensor.data_generators import translate
  from tensor2tensor.data_generators import wiki_lm
  from tensor2tensor.utils import registry
label_desc: Use image node_id 3 for calling the TranslateEnfrWmtSmallCharacters obj's underlying member method code with example usage: obj.source_data_files(dataset_split) and returns: datasets