code: def get_knowledge_sentence_with_special_tokens_only(
      knowledge_sentence: str, normalize_knowledge=False
  ):
      text = knowledge_sentence
      if normalize_knowledge:
          text = normalize_reply(text)
      return f"{TOKEN_KNOWLEDGE} {text} {TOKEN_END_KNOWLEDGE}"
  
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 2 for calling a global function with example usage: get_knowledge_sentence_with_special_tokens_only(knowledge_sentence, normalize_knowledge) and returns: TOKEN_KNOWLEDGE, str, text, str, TOKEN_END_KNOWLEDGE