access_token = None
token_expiry = None
token_uri = GOOGLE_TOKEN_URI
user_agent = 'Python client library'
revoke_uri = None
gCreds = GoogleCredentials(access_token, client_id, client_secret,
    refresh_token, token_expiry, token_uri, user_agent, revoke_uri=revoke_uri)
How to create Google API OAuth Credentials object from alternate source