class_docstr: give gold knowledge.
class_docstr_tok: ["give","gold","knowledge","."]
code: def many_episode_mutation(self, episode):
      episodes = super().many_episode_mutation(episode)
      for episode in episodes:
          assert len(episode) == 1
          if "selected_sentences" in episode[-1]:
              new_episode = copy.deepcopy(episode)
              new_episode[-1].force_set(
                  "labels",
                  [
                      self.TOKEN_DEC_KNOWLEDGE
                      + " "
                      + normalize_reply(
                          episode[-1]["selected_sentences"]
                      )
                  ],
              )
              new_episode[-1].force_set(
                  "text",
                  new_episode[-1]["text"]
                  + " "
                  + self.TOKEN_ENC_KNOWLEDGE,
              )
              yield new_episode
  
imports: from string import punctuation
  import copy
  from typing import List
  from parlai.core.mutators import register_mutator, ManyEpisodeMutator, MessageMutator
  from parlai.core.message import Message
  from parlai.mutators.flatten import FlattenMutator
  from parlai.utils.strings import normalize_reply
  from parlai.tasks.wizard_of_wikipedia.agents import TOKEN_KNOWLEDGE, TOKEN_END_KNOWLEDGE
  from parlai.tasks.wizard_of_internet import constants
  from .constants import FeedbackType, UNWANTED_TOKENS
label_desc: Use image node_id 1 for calling the GoldKnowledge obj's underlying member method code with example usage: obj.many_episode_mutation(episode) without return types