docs: public ParseTreeNode getChild(String name) throws TreeException {
  	ParseTreeNode result = null;
  	for (ParseTreeNode child : children) {
  	    if (child.getName().equals(name)) {
  		if (result != null) {
  		    throw new TreeException("Child '" + name + "'is multiply defined!");
  		}
  		result = child;
  	    }
  	}
  	return result;
      }