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

        try {
            $this->_containerUnset($store, $key);
        } catch (InvalidArgumentException $e) {
            throw $this->_createOutOfRangeException($this->__('Invalid store'),  null, $e, $store);
        } catch (OutOfRangeException $e) {
            throw $this->_createInvalidArgumentException($this->__('Invalid key'), null, $e, $key);
        }
    }