@Nullable
  public SliceLanguageSupportProvider getProvider() {
    AbstractTreeNode<SliceUsage> element = getElement();
    if (element == null) {
      return null;
    }
    SliceUsage usage = element.getValue();
    if (usage == null) {
      return null;
    }
    return usage.getSliceLanguageSupportProvider();
  }
@Nullable
  public SliceLanguageSupportProvider getProvider()