docs: def _post_parse_request(self, request, client_id='', **kwargs):
          """
          This is where clients come to refresh their access tokens
  
          :param request: The request
          :param authn: Authentication info, comes from HTTP header
          :returns:
          """
  
          request = RefreshAccessTokenRequest(**request.to_dict())
  
          try:
              keyjar = self.endpoint_context.keyjar
          except AttributeError:
              keyjar = ""
  
          request.verify(keyjar=keyjar, opponent_id=client_id)
  
          if "client_id" not in request:  # Optional for refresh access token request
              request["client_id"] = client_id
  
          logger.debug("%s: %s" % (request.__class__.__name__, sanitize(request)))
  
          return request