FluidXml\FluidInsertionHandler::insertIntegerXml PHP Method

    protected function insertIntegerXml($parent, $k, $v, $fn)
    {
        // The user has passed an XML document instance:
        // [ '<tag></tag>', DOMNode, SimpleXMLElement, FluidXml ]
        $wrapper = new \DOMDocument();
        $wrapper->formatOutput = true;
        $wrapper->preserveWhiteSpace = false;
        $v = \ltrim($v);
        if ($v[1] === '?') {
            $wrapper->loadXML($v);
            $nodes = $wrapper->childNodes;
        } else {
            // A way to import strings with multiple root nodes.
            $wrapper->loadXML("<root>{$v}</root>");
            // Algorithm 1:
            $nodes = $wrapper->documentElement->childNodes;
            // Algorithm 2:
            // $xp = new \DOMXPath($wrapper);
            // $nodes = $xp->query('/root/*');
        }
        return $this->attachNodes($parent, $nodes, $fn);
    }