public function toWeekDays($pattern)
    {
        $weekDays = $this->getWeekDays();

        $formatedDays = [];

        foreach (str_split($pattern) as $key => $day) {
            if (array_key_exists($day, $weekDays) && intval($day) === 1) {
                $formatedDays[] = $weekDays[$key];
            }
        }

        return join(', ', $formatedDays);
    }