code: def validate_memory_format(cls, memory_text: str):
      assert (
          MemoryUtils._is_r2c2_format(memory_text)
          or MemoryUtils._is_opt_prompt_format(memory_text)
          or MemoryUtils.is_opt_ft_mem_format(memory_text)
      ), f'Provided memory "{memory_text}" has invalid format for chatbot memory field.'
  
imports: import aiohttp
  import asyncio
  from enum import Enum
  import json
  import math
  from nltk.corpus import stopwords
  from nltk.tokenize import word_tokenize
  from nltk.stem import PorterStemmer
  import os
  import random
  import string
  import time
  from typing import List, Tuple, Optional, Dict, Any, Set, Union
  from parlai.agents.ir_baseline.ir_baseline import score_match, MaxPriorityQueue
  from parlai.core.dict import DictionaryAgent
  from parlai.core.message import Message
  from parlai.core.metrics import F1Metric
  from parlai.core.torch_generator_agent import PPLMetric
  import parlai.utils.logging
  import projects.bb3.constants
  import projects.bb3.prompts
  from projects.bb3.agents.module import Module
label_desc: Use image node_id 4 for calling the MemoryUtils obj's underlying member method code with example usage: obj.validate_memory_format(cls, memory_text) without return types