var isToday : Bool = false {
        didSet {
            switch isToday {
            case true:
                self.bgView.backgroundColor = CalendarView.Style.cellColorToday
                self.textLabel.textColor    = CalendarView.Style.cellTextColorToday
            case false:
                self.bgView.backgroundColor = CalendarView.Style.cellColorDefault
                self.textLabel.textColor = CalendarView.Style.cellTextColorDefault
            }
        }
    }

    var isWeekend: Bool = false {
        didSet {
            if self.isToday { return }
            switch isWeekend {
            case true:
                self.textLabel.textColor = CalendarView.Style.cellTextColorWeekend
            case false:
                self.textLabel.textColor = CalendarView.Style.cellTextColorDefault
            }
        }
    }

    override open var isSelected : Bool {
        didSet {
            switch isSelected {
            case true:
                self.bgView.layer.borderColor = CalendarView.Style.cellSelectedBorderColor.cgColor
                self.bgView.layer.borderWidth = CalendarView.Style.cellSelectedBorderWidth
            case false:
                self.bgView.layer.borderColor = CalendarView.Style.cellBorderColor.cgColor
                self.bgView.layer.borderWidth = CalendarView.Style.cellBorderWidth
            }
        }
    }