php trait 使用

trait Ahao{
    public function Say(){
        echo "那指定是不行的";
    }
}
trait HaoD{
    public function haoDSay(){
        echo "必须的";
    }
}

class TheWorldIsNotEnough {
    use Ahao;
    use HaoD;
    public function sayHello() {
        echo ‘Hello Universe!‘;
    }
}
$o = new TheWorldIsNotEnough();
$o->sayHello();
echo "<br>";
$o->Say();
echo "<br>";
$o->haoDSay();
echo "<br>";