'Google doesn\'t accept client ID and secret to be at the same time in
request parameters and in the basic authorization header in the access
token request.'

@classmethod
def _x_request_elements_filter(cls, request_type, request_elements, credentials):

    if (request_type is cls.ACCESS_TOKEN_REQUEST_TYPE):
        params = request_elements[2]
        del params['client_id']
        del params['client_secret']
    return request_elements
