code: @Override
    public Tree newTreeNode(Label parentLabel, List<Tree> children) {
      return new LabeledScoredTreeNode(lf.newLabel(parentLabel), children);
    }
docs: Create a new non-leaf tree node with the given label
  
  @param parentLabel The label for the node
  @param children    A <code>List</code> of the children of this node,
  each of which should itself be a <code>LabeledScoredTree</code>
  @return A new internal tree node