code: def get_group(self, filename: str) -> Optional[Dict[str, str]]:
      pass
  
imports: import json
  import os
  import random
  from abc import ABC, abstractmethod
  from pathlib import Path
  from typing import Dict, Optional
  import hashlib
label_desc: Use image node_id 5 for calling the CacheManager obj's underlying member method code with example usage: obj.get_group(filename) without return types