call back in render list- prestashop

Callback in Renderlist

$this->fields_list['status'] = array(
            'title' => Context::getContext()->getTranslator()->trans('Status'),
            'align' => 'center',          
            'callback'=>'PaymentStatus'
        );


public function PaymentStatus($status)
    {
        if ($status==1)
            return 'Payment Confirmed';
        else
            return 'Payment Pending';
    }