code: def check_response(self, response):
          
          if response.status_code == 401:
              raise D4S2Error(UNAUTHORIZED_MESSAGE)
          if not 200 <= response.status_code < 300:
              raise D4S2Error("Request to {} failed with {}:\n{}.".format(response.url, response.status_code,
                                                                          response.text))
docs: Raises error if the response isn't successful.
          :param response: requests.Response response to be checked