code: def act(self, obs=None):
      if not obs:
          obs = self.observation
      if obs is None:
          return {"text": "Nothing to repeat yet."}
      reply = {}
      reply["id"] = self.getID()
      knowledge = self.get_knowledge(obs)
      if not isinstance(knowledge, str):
          knowledge = random.choice(knowledge)
      reply["text"] = knowledge
      return Message(reply)
  
imports: from copy import deepcopy
  from typing import Optional, List
  from types import MethodType
  from collections import defaultdict
  from nltk.tokenize import sent_tokenize
  from nltk.corpus import stopwords
  import random
  import spacy
  import torch
  from parlai.core.agents import create_agent, create_agent_from_shared
  from parlai.core.params import ParlaiParser
  from parlai.core.opt import Opt
  from parlai.core.message import Message
  from parlai.core.agents import Agent
  from parlai.core.metrics import F1Metric
  from parlai.agents.rag.args import setup_rag_args
  from parlai.agents.bart.bart import BartAgent
  from parlai.core.metrics import normalize_answer
  from parlai.tasks.wizard_of_wikipedia.agents import TOKEN_NOCHOSEN
  from parlai.tasks.wizard_of_wikipedia.agents import TOKEN_KNOWLEDGE, TOKEN_END_KNOWLEDGE
label_desc: Use image node_id 5 for calling the OracleKnowledgeAgent obj's underlying member method code with example usage: obj.act(obs) and returns: Message, dict