我有一段Python代码，几周前（2021年10月）还在使用Google MyBusiness API：

discovery_url = 'https://developers.google.com/my-business/samples/mybusiness_google_rest_v4p5.json'

service = build(
    'mybusiness', 
    'v4', 
    credentials=credentials, 
    discoveryServiceUrl=discovery_url
)

现在，同一段代码将产生以下错误：

googleapiclient.errors.UnknownApiNameOrVersion: name: mybusiness  version: v4

根据他们的documentation，我的discoveryServiceUrl应该是：

discovery_url = 'https://developers.google.com/my-business/reference/rest'

service = build(
    'mybusiness', 
    'v4', 
    credentials=credentials, 
    discoveryServiceUrl=discovery_url
)

当我进行更改时，我得到了另一个错误：

googleapiclient.errors.HttpError: <HttpError 403 when requesting https://mybusiness.googleapis.com/$discovery/rest?version=v4 returned "The request is missing a valid API key.". Details: "The request is missing a valid API key.">

我不知道应该在发现URL中提供什么API密钥？