php构造函数求大神指教！

class Person{
private $name;
private $age;
private $gender;

public function __construct($name,$age,$gender){    $this->setName($name);    $this->setAge($age);    $this->setGender($gender);}public function setName($name){    $this->name = $name;}

}

// ... getter setter 方法

}

$peron = new Person("lee",18,'男');

?>

为什么报错呢 ？