private Object extractSelectedNodesNavigatables() {
    final List<Navigatable> navigatables = new ArrayList<>();
    for (ExecutionNode each : getSelectedNodes()) {
      List<Navigatable> navigatable = each.getNavigatables();
      navigatables.addAll(navigatable);
    }
    return navigatables.isEmpty() ? null : navigatables.toArray(Navigatable.EMPTY_NAVIGATABLE_ARRAY);
  }
private Object extractSelectedNodesNavigatables()