@Override
  public @Nullable ElementPresentationTemplate getPresentationTemplate() {
    Ref<ElementPresentationTemplate> ref = myPresentationTemplate;
    if (ref == null) {
      myPresentationTemplate = ref = Ref.create(calcPresentationTemplate());
    }
    return ref.get();
  }
@Override
  public @Nullable ElementPresentationTemplate getPresentationTemplate()