JTAppleCalendar -如何停止随机重复的单元格？

Question

我在cellForItemAt方法中画了一个圆，对于特定的条件，如下所示：

    if cellState.date == CalendarModel.DUE_DATE {
        let shapeLayer = CAShapeLayer()

        let circlePath = UIBezierPath(arcCenter: CGPoint(x: (cell.layer.frame.size.width)/2,y: (cell.layer.frame.size.height)/2), radius: CGFloat(15), startAngle: CGFloat(0), endAngle:CGFloat(Double.pi * 2), clockwise: true)


        shapeLayer.path = circlePath.cgPath

        //change the fill color
        shapeLayer.fillColor = UIColor.clear.cgColor
        //you can change the stroke color
        shapeLayer.strokeColor = UIColor.FlatColor.Blue.midnightBlue.cgColor
        //you can change the line width
        shapeLayer.lineWidth = 1.0
        cell.layer.addSublayer(shapeLayer)
    }

这个圆圈一直在随机重复。我尝试在willDisplayCell中使用下面的代码，但是它会删除单元格中的所有内容。

func calendar(_ calendar: JTAppleCalendarView, willDisplay cell: JTAppleCell, forItemAt date: Date, cellState: CellState, indexPath: IndexPath) {
    // comment
    cell.layer.sublayers?.forEach { $0.removeFromSuperlayer() }
}

如何具体删除cellForItemAt中添加的shapeLayer？任何帮助都将不胜感激。谢谢。