subclassing the UIViewController into UILoadingVeiwController

UILoadingViewController.swift

class UILoadingViewController: UIViewController{
    func showWaiting(message: String){
        print("show waiting from UILoadingViewController with message \(message)")
    }
}

class LoginVC : UILoadingViewController{
    func buttonTapped(){
        showWaiting(message: "show me!")
    }
    // letter if we have new developer joined, and they try to overrid this function. its fragile!!
    override func showWaiting(message: String) {
        print("i am dangerous!")
    }
}

class AboutVC : UIViewController {
    // we cannot see any showWaiting func from here....
}