iOS Swift dashed lines extension

.swift

public let kShapeDashed : String = "kShapeDashed"

extension UIView {
    
    func removeDashedBorder(_ view: UIView) {
        view.layer.sublayers?.forEach {
            if kShapeDashed == $0.name {
                $0.removeFromSuperlayer()
            }
        }
    }

    func addDashedBorder(width: CGFloat? = nil, height: CGFloat? = nil, lineWidth: CGFloat = 2, lineDashPattern:[NSNumber]? = [6,3], strokeColor: UIColor = UIColor.red, fillColor: UIColor = UIColor.clear) {
        
        
        var fWidth: CGFloat? = width
        var fHeight: CGFloat? = height
        
        if fWidth == nil {
            fWidth = self.frame.width
        }
        
        if fHeight == nil {
            fHeight = self.frame.height
        }
        
        let shapeLayer:CAShapeLayer = CAShapeLayer()

        let shapeRect = CGRect(x: 0, y: 0, width: fWidth!, height: fHeight!)
        
        shapeLayer.bounds = shapeRect
        shapeLayer.position = CGPoint(x: fWidth!/2, y: fHeight!/2)
        shapeLayer.fillColor = fillColor.cgColor
        shapeLayer.strokeColor = strokeColor.cgColor
        shapeLayer.lineWidth = lineWidth
        shapeLayer.lineJoin = kCALineJoinRound
        shapeLayer.lineDashPattern = lineDashPattern
        shapeLayer.name = kShapeDashed
        shapeLayer.path = UIBezierPath(roundedRect: shapeRect, cornerRadius: 5).cgPath
        
        self.layer.addSublayer(shapeLayer)
    }
    
}

Can you explain how it works on dynamic view?