public function xpathSingle($strXpathQuery)
    {
        $arrResults = $this->xpath($strXpathQuery);

        if ($arrResults === false) {
            //throw new Exception('xpathElement returned an unspecified error on '.$strXpathQuery);
            return null;
        }

        if (is_array($arrResults) && count($arrResults) == 0) {
            return null;
        } else {
            if (count($arrResults) > 1) {
                throw new Exception(
                    'xpathSingle expects a single element as result, got ' . count($arrResults) . ' elements instead.'
                );
            } else {
                return current($arrResults);
            }
        }
    }