code: def _query_once(self, urls):
          
          request_body = '{}\n{}'.format(len(urls), '\n'.join(urls))
          response = post(self._request_address, request_body)
          try:
              response.raise_for_status()
          except HTTPError as error:
              if response.status_code == 401:
                  msg = 'The API key is not authorized'
                  raise_from(UnathorizedAPIKeyError(msg), error)
              else:
                  raise
          return response
docs: Perform a single POST request using lookup API.
  
          :param urls: a sequence of URLs to put in request body
          :returns: a response object
          :raises UnathorizedAPIKeyError: when the API key for this
          instance is not valid
          :raises HTTPError: if the HTTPError was raised for a HTTP code
          other than 401, the exception is reraised