我已经创建了具有blur功能的扩展的Blurable协议(protocol)。protocolBlurable{}extensionBlurablewhereSelf:UIView{funcblur(witheffect:UIBlurEffectStyle){letblurEffect=UIBlurEffect(style:effect)letblurEffectView=UIVisualEffectView(effect:blurEffect)blurEffectView.frame=boundsaddSubview(blurEffectView)}}现在我想添加unblur功能。如