}
public ConfigElement combine(ConfigElement combinee) {
HierarchicalConfiguration conf2 = this.configuration;
HierarchicalConfiguration conf1 = ((ConfigurationConfig) combinee).configuration;
NodeCombiner combiner = new UnionCombiner();
CombinedConfiguration cc = new CombinedConfiguration(combiner);
cc.addConfiguration(conf1);
cc.addConfiguration(conf2);
ConfigurationConfig combined = new ConfigurationConfig();
cc.setExpressionEngine(new XPathExpressionEngine());