codeigniter MY_Controller not found

i’m using the Codeigniter.2.1.3 for a website, so i need to extend the CI_Controller so i can add a method to be executed with all controllers so i did what’s in the user_guide:

creating a file named MY_Controller.php in the application/core folder the creating in it MY_Controller Class that extends the CI_Controller, the changing my regular controller to extend the MY_controller like this: MY_controller.php:

class MY_Controller extends CI_Controller{
    protected $page;
    # Constructor
    function __construct (){
        parent::__construct();
        #code shared with all controllers
    }
    public function get_page(){
        #code to get_the right page here
    }
}

regular controller named Regular.php:

class Regular extends MY_Controller{
     public function __construct(){
         parent::__construct();
     }
     public function index(){
          $this->get_page();
     }
}

but the following error keep appearing:

Fatal error: Class ‘MY_Controller’ not found in /var/www/immo/CodeIgniter_2.1.3/application/controllers/regular.php on line 2

You would need to include your MY_Controller class or auto-load it. I suggest you auto-load it by adding the following to your application/config/config.php file.

function __autoload($class)
{
    if (strpos($class, 'CI_') !== 0)
    {
        if (file_exists($file = APPPATH . 'core/' . $class . EXT))
        {
            include $file;
        }
    }
}