Handling Mac menu commands with SwfitUI

It seems that the examples from WWDC on handling commands by extending command doesn't work since Command no longer exists and the onCommand fucntion wants a selector. It also seems that my custom view can't be made focusable. i have the follwong code.

struct ContentView: View {
    var body: some View {
        MyView()
            .focusable() { print("\($0)") }
            .onCommand(Selector("onAny:")) {
                print("foo")
        }
    }
}

struct MyView: View {
    var body: some View {
        Rectangle()
            .fill(Color.blue)
            .frame(width: 400, height: 400, alignment: .topLeading)
    }
}
struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

Is there a proper supported way to do this. Or is SwiftUI not ready for real mac app developement yet? I can't add support for copy or paste yet it seems that the view won't become a first responder.