php 接口继承接口

<?php
interface User
{
function getName();
function setName($_name);
}
interface VipUser extends User //VipUser继承User接口
{
function getDiscount(); //此处添加了一个抽象的方法
}
class Vip implements VipUser
{
private $name;
private $discount = 0.8; //折扣变量
function getName() {
return $this->name;
}
function setName($_name) {
$this->name = $_name;
}
function getDiscount() {
return $this->discount;
}
}

$v = new Vip;
echo $v->getDiscount();