class_docstr: En-Fr translation with added French data, back-translated.
class_docstr_tok: ["En-Fr","translation","with","added","French","data",",","back-translated","."]
docstr: List of pairs of files with matched back-translated data.
docstr_tok: ["List","of","pairs","of","files","with","matched","back-translated","data","."]
code: def backtranslate_data_filenames(self):
      """List of pairs of files with matched back-translated data."""
      # Files must be placed in tmp_dir, each similar size to authentic data.
      return [("fr_mono_en.txt", "fr_mono_fr.txt")]
  
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 4 for calling the TranslateEnfrWmt32kWithBacktranslateFr obj's underlying member method code with example usage: obj.backtranslate_data_filenames() and returns: list