swift 类继承

import Foundationclass Student{    func sayHi()    {         print("student say hi")    }}class Persion:Student{        var _name:String        init(name:String) {        self._name = name    }        override func sayHi() {        super.sayHi()        print("say \(self._name)")    }}var persion = Persion(name: "yihong")persion.sayHi()