public function sort($callbackFunction)
    {
        $items = iterator_to_array($this, false);
        usort($items, $callbackFunction);

        /** @var \Tx_Oelib_Model $item */
        foreach ($items as $item) {
            $this->detach($item);
            $this->attach($item);
        }

        $this->markAsDirty();
    }