Access LargeTitleView in swift

largeTitleView.swift

  var largeTitleView:UIView{
        if let navBarSubviews = navigationController?.navigationBar.subviews {
            for subView in navBarSubviews where NSStringFromClass(type(of: subView)).contains("LargeTitle"){
                return subView
            }
        }
        assert(false, "A large title view is expected on viewDidAppear")
        return UIView()
    }