public function getString($indent = 2, $wordWrap = false)
    {
        $res = $this->driverInstance->getString($indent, $wordWrap);
        if (!$this->isString($res) && !$this->isStringObject($res)) {
            throw new YamlException('YamlInterface method _getString() must return a string or StringObject.');
        }

        return StdObjectWrapper::toString($res);
    }