Fatal error: Call to undefined method Model::_construct() in C:\xampp\htdocs\kohana\application\models\album.php on line 8

在application/model/下的代码是：加载Model时被警告说该函数不存在。下面的parent::_construct();就运行错误了

<?php
defined('SYSPATH')OR die('No direct access allowed');
class Album_Model extends Model
{
private $album_table;
public function __construct()
{
parent::_construct();
//$this->album_table='albums';

}
}