docs: private static boolean isDefault(Tree<Node> tree){
  		Tree<Node> flag = tree;
  		while(!flag.isLeaf()&&flag.children.size()==1)
  			flag = flag.getFirstChild();
  		if(flag.isLeaf()&&flag.label.getTag().equals("-NONE-"))
  			return true;
  		else
  			return false;
  	}