class_docstr: Adds the dialogue sentence to the input.
  
  But only a single time.
class_docstr_tok: ["Adds","the","dialogue","sentence","to","the","input",".","But","only","a","single","time","."]
code: def message_mutation(self, message: Message) -> Message:
      new_message = message.copy()
      if (
          "text" not in message
          or "labels" not in message
          or not message["labels"]
      ):
          return message
      if "dialogue_response" in new_message:
          # checked_sentence_as_label was applied before
          labels = new_message["dialogue_response"]
      else:
          labels = new_message["labels"]
      dialogue_response = labels[0]
      text = new_message.pop("text")
  
      text += f"\n{CONST.TOKEN_LABEL} {dialogue_response} {CONST.TOKEN_END_LABEL}"
      new_message["text"] = text
  
      return new_message
  
imports: from parlai.core.mutators import register_mutator, MessageMutator, ManyEpisodeMutator
  from parlai.core.message import Message
  import parlai.tasks.wizard_of_internet.constants
  import random
label_desc: Use image node_id 1 for calling the AddLabel obj's underlying member method code with example usage: obj.message_mutation(message) and returns: new_message, message