Create a rectangle with just two rounded corners in swift?

Question

I need to create a rectangle that have just two rounded corners in swift (Objective C code also ok).

At the moment my code is creating two rectangles with

Answer 1

extension CACornerMask {

    public static var leftBottom     : CACornerMask { get { return .layerMinXMaxYCorner}}
    public static var rightBottom    : CACornerMask { get { return .layerMaxXMaxYCorner}}
    public static var leftTop        : CACornerMask { get { return .layerMaxXMinYCorner}}
    public static var rightTop       : CACornerMask { get { return .layerMinXMinYCorner}}
}

extension CALayer {

    func roundCorners(_ mask:CACornerMask,corner:CGFloat) {
        self.maskedCorners = mask
        self.cornerRadius = corner
    }
}

self.viewBack.layer.roundCorners([.leftBottom,.rightBottom], corner: 23)