class_docstr: Abstract class for dialog problems.
code: def open_6_files(self):
      trainsource = open(
          os.path.join(self._data_dir, "trainSource.txt"), "w"
      )
      traintarget = open(
          os.path.join(self._data_dir, "trainTarget.txt"), "w"
      )
      devsource = open(
          os.path.join(self._data_dir, "devSource.txt"), "w"
      )
      devtarget = open(
          os.path.join(self._data_dir, "devTarget.txt"), "w"
      )
      testsource = open(
          os.path.join(self._data_dir, "testSource.txt"), "w"
      )
      testtarget = open(
          os.path.join(self._data_dir, "testTarget.txt"), "w"
      )
  
      return (
          trainsource,
          traintarget,
          devsource,
          devtarget,
          testsource,
          testtarget,
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  import re
  import tarfile
  import zipfile
  import requests
  from tensor2tensor.data_generators import generator_utils
  from tensor2tensor.data_generators import problem
  from tensor2tensor.data_generators import text_encoder
  from tensor2tensor.data_generators import text_problems
  from tensor2tensor.data_generators.text_problems import VocabType
  from tensor2tensor.layers import modalities
  from tensor2tensor.utils import metrics
  import tensorflow.compat.v1
label_desc: Use image node_id 33 for calling the DialogAbstract obj's underlying member method code with example usage: obj.open_6_files() and returns: trainsource,  traintarget,  devsource,  devtarget,  testsource,  testtarget