code: def extract_knowledge(txt: str) -> List[str]:
      if not txt or not txt.split():
          return []
      entities = extract_entities(txt)
      return [
          e.lower() for e in (entities if entities else txt.split())
      ]
  
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 a global function with example usage: extract_knowledge(txt) and returns: unknown, list