protected function _getData($key)
    {
        $store = $this->_getDataStore();

        try {
            $result = $this->_containerGet($store, $key);
        } catch (OutOfRangeException $e) {
            throw $this->_createInvalidArgumentException($this->__('Invalid key'), null, $e, $key);
        }

        return $result;
    }