public function toUnsignedXML() : DOMElement
    {
        $root = parent::toUnsignedXML();

        if ($this->inResponseTo !== null) {
            $root->setAttribute('InResponseTo', $this->inResponseTo);
        }

        $status = $this->document->createElementNS(Constants::NS_SAMLP, 'Status');
        $root->appendChild($status);

        $statusCode = $this->document->createElementNS(Constants::NS_SAMLP, 'StatusCode');
        $statusCode->setAttribute('Value', $this->status['Code']);
        $status->appendChild($statusCode);

        if (!is_null($this->status['SubCode'])) {
            $subStatusCode = $this->document->createElementNS(Constants::NS_SAMLP, 'StatusCode');
            $subStatusCode->setAttribute('Value', $this->status['SubCode']);
            $statusCode->appendChild($subStatusCode);
        }

        if (!is_null($this->status['Message'])) {
            Utils::addString($status, Constants::NS_SAMLP, 'StatusMessage', $this->status['Message']);
        }

        return $root;
    }