extension Publisher where Failure == Never{
    func present<ToVC:UIViewController, P>(from fromVC:UIViewController,
                                           to toVC:ToVC,
                                           assignee: KeyPath<ToVC, P>,
                                           keyPath: ReferenceWritableKeyPath<P,Output>,
                                           animated:Bool = true) -> AnyCancellable {
        sink {[weak fromVC, weak toVC] (output) in
            guard let to = toVC, let from = fromVC else {return}
            let toBeAssign = to[keyPath: assignee]
            toBeAssign[keyPath: keyPath] = output
            from.present(to, animated: true, completion: nil)
        }
    }
}