@Override
    public LighterASTNode getParent(@NotNull LighterASTNode node) {
      if (node instanceof ProductionMarker) {
        return ((ProductionMarker)node).myParent;
      }
      if (node instanceof Token) {
        return ((Token)node).myParentNode;
      }
      throw new UnsupportedOperationException("Unknown node type: " + node);
    }
@Override
    public LighterASTNode getParent(@NotNull LighterASTNode node)