Convert an array to XML in PHP

function array_to_xml(array $data, SimpleXMLElement $xml)
{
    foreach ($data as $key => $value) {
        $child = is_int($key) ? 'item' : (string) $key;

        is_array($value)
            ? array_to_xml($value, $xml->addChild($child))
            : $xml->addChild($child, htmlspecialchars($value));
    }

    return $xml;
}