如何在swift3中重写高分

import UIKit

class CustomImageView: UIImageView {
    
    override var image: UIImage? {
        get {
            return super.image
        }
        set {
            if let newImage = newValue {
                let scaledImage = scaleImage(image: newImage, toSize: CGSize(width: 100, height: 100))
                super.image = scaledImage
            } else {
                super.image = nil
            }
        }
    }
    
    private func scaleImage(image: UIImage, toSize size: CGSize) -> UIImage {
        UIGraphicsBeginImageContextWithOptions(size, false, 0.0)
        image.draw(in: CGRect(x: 0, y: 0, width: size.width, height: size.height))
        let scaledImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return scaledImage ?? image
    }
}