public static function secondsBetweenDates($start, $end, $absolute = true, $timezone = 'Europe/Prague')
    {
        $timezoneObj = new \DateTimeZone($timezone);
        $date = new DateTime($end, $timezoneObj);
        $diff = $date->diff(new DateTime($start, $timezoneObj), $absolute);

        return ($diff->invert ? -1 : 1) * (($diff->days * 86400) + ($diff->h * 3600) + ($diff->i * 60) + $diff->s);
    }