private function getWeekDays()
    {
        if (empty(self::$weekDays) && ($this->translator instanceof TranslatorInterface)) {
            self::$weekDays = [
                $this->translator->trans('calendar.weekdays.monday', [], 'default'),
                $this->translator->trans('calendar.weekdays.tuesday', [], 'default'),
                $this->translator->trans('calendar.weekdays.wednesday', [], 'default'),
                $this->translator->trans('calendar.weekdays.thursday', [], 'default'),
                $this->translator->trans('calendar.weekdays.friday', [], 'default'),
                $this->translator->trans('calendar.weekdays.saturday', [], 'default'),
                $this->translator->trans('calendar.weekdays.sunday', [], 'default'),
            ];
        }

        return self::$weekDays;
    }