class_docstr: Adds the checked sentence to the end of the text.
  
  E.g. run with: parlai display_data -t wizard_of_internet -n 100 -dt valid --mutators
  flatten,add_checked_sentence_to_input_woi
code: def checked_sentence_kword(self):
      return CONST.SELECTED_SENTENCES
  
imports: import torch
  from parlai.core.mutators import register_mutator, MessageMutator, ManyEpisodeMutator
  from typing import Optional
  from parlai.core.opt import Opt
  from parlai.core.message import Message
  from parlai.core.params import ParlaiParser
  import parlai.tasks.wizard_of_internet.constants
  from parlai.tasks.wizard_of_wikipedia.mutators import AddLabel, AddLabelLM, CheckedSentenceAsLabel, AddCheckedSentence
label_desc: Use image node_id 1 for calling the AddCheckedSentence obj's underlying member method code with example usage: obj.checked_sentence_kword() and returns: CONST