public function setDayOfWeek($_day, $_week)
    {
        if (!($_day >= 0 && $_day < 7)) {
            throw new Exception("Invalid day of week parameter, must be >= 0 & < 7");
        }

        if (!($_week >= 0 && $_week < 4)) {
            throw new Exception("Invalid week number, must be >= 1 & < 4");
        }

        $this->dayOfWeek = $_day;
        $this->week = $_week;
    }