code: func (handler ControllerHandler) isValid() bool {
  	controller := handler.factory()
  	rController := reflect.ValueOf(controller)
  	method := rController.MethodByName(handler.methodName)
  	if (method == reflect.Value{}) {
  		panic("No such method: " + handler.methodName)
  	}
  	typeOfMethod := method.Type()
  
  	var r *Response
  	responseType := reflect.TypeOf(r).Elem()
  
  	return (method.Kind() == reflect.Func) &&
  		(typeOfMethod.NumMethod() == 0) &&
  		(typeOfMethod.NumOut() == 1) &&
  		typeOfMethod.Out(0) == responseType
  
  }
docs: // isValid checks that the controller and method specifies
  // will sucessfully execute if getResponse is called on it