code: def _parse_regr_response(self, response, uri=None, new_authzr_uri=None,
                               terms_of_service=None):
          
          links = _parse_header_links(response)
          if u'terms-of-service' in links:
              terms_of_service = links[u'terms-of-service'][u'url']
          if u'next' in links:
              new_authzr_uri = links[u'next'][u'url']
          if new_authzr_uri is None:
              raise errors.ClientError('"next" link missing')
          return (
              response.json()
              .addCallback(
                  lambda body:
                  messages.RegistrationResource(
                      body=messages.Registration.from_json(body),
                      uri=self._maybe_location(response, uri=uri),
                      new_authzr_uri=new_authzr_uri,
                      terms_of_service=terms_of_service))
              )
docs: Parse a registration response from the server.