swift change background color of view inside a view code example

Example: how to change background color of stackview swift

extension UIStackView {
    func addBackground(color: UIColor) {
        let subView = UIView(frame: bounds)
        subView.backgroundColor = color
        subView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        insertSubview(subView, at: 0)
    }
}