code: public void addHandlers(Object... handlers) {
          for ( Object handler : handlers) {
              //assert that this is a Handler
              checkValidHandlerType(handler);
  
              StepInvokerProvider invokerFactory = new HandlerClassInvokerFactory(handler);
              List<StepInvoker> invokers = invokerFactory.getStepInvokers();
  
              if (invokers.isEmpty()) {
                  Class<?> handlerClass = handler.getClass();
                  log.warn(String.format("Cannot export object of type (%s) it either:  1) Has no methods that declare the @Step annotation  " +
                          "2) Returns zero StepInvoker's from a StepInvokerProvider instance", handlerClass.getName()));
              }
  
              for ( StepInvoker i : invokers) {
                  addStepInvoker(i);
              }
          }
      }
docs: Add handler classes containing the step definitions to publish
  This must be done before publish is called (or while the step publisher is disconnected)