public List<ParseTreeNode<command.CommandInterface>> getChildListAt(int index)
     throws IndexOutOfBoundsException {
   return children.getChildListAt(index);
 }
 public void addChildAt(int index, List<ParseTreeNode<command.CommandInterface>> child)
     throws IndexOutOfBoundsException {
   children.addChildListAt(index, child);
 }
 public void removeChildListAt(int index) throws IndexOutOfBoundsException {
   children.removeChildListAt(index);
 }
 public void addChild(List<ParseTreeNode<command.CommandInterface>> child) {
   children.addChildList(child);
 }