Problem with validation an unique field

[eluser]Mr.SoOoMa[/eluser]
i know that, i read it before but i didn't understand all of it because i told you that i'm new in CI & english isn't my native language

i changed it to :

Code:

<?php if (!defined('BASEPATH')) exit('No direct script access allowed');
class MY_Form_validation extends CI_Form_validation {

    function __construct()
    {
        parent::__construct();
        $CI =& get_instance();
        $CI->load->model("Clients_model","clients");
    }
      public  function edit_unique_email($email,$id){
        if($CI->clients->if_email_unique($email,$id)==0){
            return true;
        }
        else{
            return false;
        }
    }
    
    }

but i have the problem : Fatal error: Call to a member function if_email_unique() on a non-object in C:\AppServ\www\clever\application\libraries\MY_Form_validation.php on line 11

please can u help me