docs: public ModelService lookupService(String serviceName){
          HttpResponse result = invoker.invoke("/service/" + serviceName , null, HttpMethod.GET);
  
          if (result.getHttpCode() != HTTP_OK) {
              throw new ServiceException(ErrorCode.REMOTE_DIRECTORY_SERVER_ERROR,
                      "HTTP Code is not OK, code=%s", result.getHttpCode());
          }
  
          ModelService service = _deserialize(result.getRetBody(), ModelService.class);
          return service;
      }