class_docstr: Problem spec for WMT En-Ro translation.
code: def source_data_files(self, dataset_split):
      train = dataset_split == problem.DatasetSplit.TRAIN
      return _ENRO_TRAIN_DATASETS if train else _ENRO_TEST_DATASETS
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import random
  from tensor2tensor.data_generators import problem
  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 2 for calling the TranslateEnroWmt8k obj's underlying member method code with example usage: obj.source_data_files(dataset_split) and returns: unknown