code: func InterceptMethod(intc InterceptorMethod, when When) {
  	methodType := reflect.TypeOf(intc)
  	if methodType.Kind() != reflect.Func || methodType.NumOut() != 1 || methodType.NumIn() != 1 {
  		log.Fatalln("Interceptor method should have signature like",
  			"'func (c *AppController) example() revel.Result' but was", methodType)
  	}
  
  	interceptors = append(interceptors, &Interception{
  		When:     when,
  		method:   intc,
  		callable: reflect.ValueOf(intc),
  		target:   methodType.In(0),
  	})
  }
docs: // InterceptMethod installs an interceptor method that applies to its own Controller.
  //   func (c AppController) example() revel.Result
  //   func (c *AppController) example() revel.Result