code: def dataset_version(self):
      # Year of the opensubtitles dataset creation.
      return 2011
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import collections
  import os
  import re
  import zipfile
  from tensor2tensor.data_generators import dialog_abstract
  from tensor2tensor.data_generators import text_encoder
  from tensor2tensor.utils import registry
label_desc: Use image node_id 1 for calling the DialogOpensubtitles64k2011 obj's underlying member method code with example usage: obj.dataset_version() and returns: int