public static function hasRelativeKeywords($time)
    {
        if (strtotime($time) === false) {
            return false;
        }

        $date1 = new DateTime('2000-01-01T00:00:00Z');
        $date1->modify($time);
        $date2 = new DateTime('2001-12-25T00:00:00Z');
        $date2->modify($time);

        return $date1 != $date2;
    }