✅ Getting Button Command Parameter Avalonia

public HomeViewModel()
{
    IObservable<bool> selectionOk = this.WhenAnyValue(
      x => x.SelectedDifficulty,
      x => x != "Select One");

    Play = ReactiveCommand.Create(
        PlayGame,
        selectionOk);
}

public void PlayGame() { }
public ReactiveCommand<Unit, Unit> Play { get; }

<Button Command={Binding Play} CommandParameter="Something" />