public function toXml()
    {
        $data = $this->toArray();

        $writer = new \SimpleXMLElement('<Table/>');
        $headers = [];
        foreach ($data as $index => $item) {

            if ($index==0) {
                $headers = $item;
            }
            $child = $writer->addChild('Row');
            foreach ($headers as $k => $name) {
                $child->addChild('Cell', $item[$k]);
            }
        }

        $dom = dom_import_simplexml($writer)->ownerDocument;
        $dom->formatOutput = true;
        // $dom->save($filename);
        return $dom->saveXML();
    }