public static function isPrintfIsoFormat($isoFormat)
    {
        $subPattern = self::getPrintfFormatSpecifier();
        $pattern = '/(?:(?:[^%]|^)(?:%%)+(' . $subPattern . '))|(?:(?:[^%])(' . $subPattern . '))|(?:^(' . $subPattern . '))/u';

        $matches = array();
        preg_match_all($pattern, $isoFormat, $matches);

        if (count($matches[1]) + count($matches[2]) + count($matches[3]) > 0) {
            // There is at least one format specifier in the string.
            return true;
        } else {
            return false;
        }
    }