function parseXML(xml, log, cb) {
    if (!xml) {
        log.debug('request xml is missing');
        return cb(errors.MalformedXML);
    }
    return xml2js.parseString(xml, (err, result) => {
        if (err) {
            log.debug('request xml is malformed');
            return cb(errors.MalformedXML);
        }
        return cb(null, result);
    });
}
Handle initial parsing of XML using the `xml2js.parseString` method
@param {string} xml - The XML to be parsed
@param {object} log - Werelogs logger
@param {function} cb - Callback to call
@return {undefined}