Magento: Success message session not work

comment out default formatting

if ($codeLength) {
    if ($isCodeLengthValid && $couponCode == $this->_getQuote()->getCouponCode()) {
       // $this->_getSession()->addSuccess(
       //     $this->__('Coupon code "%s" was applied.', Mage::helper('core')->escapeHtml($couponCode))
      //  );
        
        $message = 'Coupon code "'. Mage::helper('core')->escapeHtml($couponCode) .'" was applied.';
        Mage::getSingleton('core/session')->addSuccess($message);
        
    } else {
        //$this->_getSession()->addError(
     //       $this->__('Coupon code "%s" is not valid.', Mage::helper('core')->escapeHtml($couponCode))
      //  );
        
        $message = 'Coupon code "'.Mage::helper('core')->escapeHtml($couponCode).'" is not valid.';
        Mage::getSingleton('core/session')->addError($message);
        
    }
} else {
   // $this->_getSession()->addSuccess($this->__('Coupon code was canceled.'));
    $message = 'Coupon code was canceled.';
    Mage::getSingleton('core/session')->addSuccess($message);
}