code: def __init__(self, api_type):
      self._api_token = None
      self._credential = None
      self._is_azure_ad = api_type in ("azure_ad", "azuread")
      self._key_configured = "OPENAI_API_KEY" in os.environ
  
      if self._is_azure_ad and not self._key_configured:
          try:
              from azure.identity import DefaultAzureCredential
          except ImportError:
              raise mlflow.MlflowException(
                  "Using API type `azure_ad` or `azuread` requires the package"
                  " `azure-identity` to be installed."
              )
          self._credential = DefaultAzureCredential()
  
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 to create a new _OAITokenHolder object  with example: obj = _OAITokenHolder(api_type)