How to control an UIView's rounded corners separately using @IBInspectable in Swift 3?

Here is my current code:

override func viewDidLoad() {
    super.viewDidLoad()

    let rect = Draw(frame: CGRect(
        origin: CGPoint(x: 50, y: 50),
        size: CGSize(width: 100, height: 100)))
    self.view.addSubview(rect)
}