code: def secret_key(self):
      return self.value.lower()
  
imports: import json
  import os
  import time
  from contextlib import contextmanager
  from enum import Enum
  from typing import NamedTuple, Optional
  from unittest import mock
  import requests
  import mlflow
label_desc: Use image node_id 1 for calling the _OpenAIEnvVar obj's underlying member method code with example usage: obj.secret_key() and returns: self