class_docstr: Paraphrase problem.
docstr: If set to true, generates data in the following way.
  
  sentence1 -> sentence2
  sentence2 -> sentence1
code: def bidirectional(self):
      """If set to true, generates data in the following way.
  
      sentence1 -> sentence2
      sentence2 -> sentence1
      """
      raise NotImplementedError()
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import collections
  import io
  import json
  import os
  import zipfile
  from tensor2tensor.data_generators import generator_utils
  from tensor2tensor.data_generators import problem
  from tensor2tensor.data_generators import text_problems
  from tensor2tensor.utils import registry
  import tensorflow.compat.v1
label_desc: Use image node_id 1 for calling the ParaphraseGenerationProblem obj's underlying member method code with example usage: obj.bidirectional() without return types