class SomeViewController: UIViewControlelr, FirstAppearing {
    override func viewDidLoad() {
        super.viewDidLoad()
        viewWillAppearOnce() {
            print("Wahahaha!") // not working!!
        }
    }

    override func viewWillAppear(animated: Bool) {
        self.clearsSelectionOnViewWillAppear = self.splitViewController!.collapsed
        super.viewWillAppear(animated)
        viewWillAppearOnce() {
            // do something
            print("Once call,",__FUNTION__)
        }
    }

    override func viewDidAppear(animated: Bool) {
        super.viewDidAppear(animated)
        viewDidAppearOnce() {
            // do something
            print("Once call,",__FUNTION__)
        }
    }
}