使用服务帐户密钥的Google Drive Python API授权

我有以下Google云平台项目的服务帐户json凭据文件:

如何使用此服务帐户向Google Drive API进行身份验证?例如,当我尝试执行以下操作时:

from googleapiclient.discovery import build
from httplib2 import Http
from oauth2client import file, client, tools

SCOPES = 'https://www.googleapis.com/auth/drive.metadata.readonly'

flow = client.flow_from_clientsecrets('mykey.json', SCOPES)
creds = tools.run_flow(flow, store)
service = build('drive', 'v3', http=creds.authorize(Http()))

results = service.files().list(pageSize=10, fields="nextPageToken, files(id, name)").execute()
items = results.get('files', [])

我在运行 flow 命令,该命令抱怨密钥文件的格式不是以 web 或 installed :

Invalid file format. See https://developers.google.com/api-client-library/python/guide/aaa_client_secrets
Expected a JSON object with a single property for a "web" or "installed" application 

有没有办法用上面的键列出我的Google服务帐户的驱动器文件?如果是的话,怎么办?