即使我正在使用OAuth，也缺少API键

Question

我是初学者。我正在尝试与Google API合作。我正在使用OAuth将请求发送到Google Calendar API。但是，我会遇到错误403：

{
"error": {
    "code": 403,
    "message": "The request is missing a valid API key.",
    "errors": [
      {
        "message": "The request is missing a valid API key.",
        "domain": "global",
        "reason": "forbidden"
      }
    ],
    "status": "PERMISSION_DENIED"
  }
}

以下问题 google日历”使用OAuth 建议使用：

google.calendar({ version: "v3", auth: client })

但是我的代码由Google提供：

service = build('calendar', 'v3', credentials=creds)

因此建议的解决方案不适用。

我的完整代码与Google API提供的“ QuickStart.py”相同，但client_secre_file的名称：

from __future__ import print_function

import datetime
import os.path

from google.auth.transport.requests import Request
from google.oauth2.credentials import Credentials
from google_auth_oauthlib.flow import InstalledAppFlow
from googleapiclient.discovery import build
from googleapiclient.errors import HttpError

# If modifying these scopes, delete the file token.json.
SCOPES = ['https://www.googleapis.com/auth/calendar.readonly']


def main():
    """Shows basic usage of the Google Calendar API.
    Prints the start and name of the next 10 events on the user's calendar.
    """
    creds = None
    # The file token.json stores the user's access and refresh tokens, and is
    # created automatically when the authorization flow completes for the first
    # time.
    if os.path.exists('token.json'):
        creds = Credentials.from_authorized_user_file('token.json', SCOPES)
    # If there are no (valid) credentials available, let the user log in.
    if not creds or not creds.valid:
        if creds and creds.expired and creds.refresh_token:
            creds.refresh(Request())
        else:
            flow = InstalledAppFlow.from_client_secrets_file(
                'client_secret_desktop.json', SCOPES)
            creds = flow.run_local_server(port=0)
        # Save the credentials for the next run
        with open('token.json', 'w') as token:
            token.write(creds.to_json())

    try:
        service = build('calendar', 'v3', credentials=creds)

        # Call the Calendar API
        now = datetime.datetime.utcnow().isoformat() + 'Z'  # 'Z' indicates UTC time
        print('Getting the upcoming 10 events')
        events_result = service.events().list(calendarId='primary', timeMin=now,
                                              maxResults=10, singleEvents=True,
                                              orderBy='startTime').execute()
        events = events_result.get('items', [])

        if not events:
            print('No upcoming events found.')
            return

        # Prints the start and name of the next 10 events
        for event in events:
            start = event['start'].get('dateTime', event['start'].get('date'))
            print(start, event['summary'])

    except HttpError as error:
        print('An error occurred: %s' % error)


if __name__ == '__main__':
    main()

我的凭据配置中可能存在问题？