code: def __getitem__(self, key: str) -> str:
      return self._tokens[key]
  
imports: from typing import Optional, Dict, Tuple
  import base64
  import collections.abc
  import os
  import json
  import logging
  from hailtop.config import get_deploy_config
  from hailtop.utils import first_extant_file
label_desc: Use image node_id 6 for calling the Tokens obj's underlying member method code with example usage: obj.__getitem__(key) and returns: self