// merge multi-nodes by merging their members.
else if(MultiNode.class.isAssignableFrom(mergingDataValue.getClass())
&& MultiNode.class.isAssignableFrom(existingDataValue.getClass())) {
MultiNode existingMultiNode = (MultiNode) existingDataValue;
MultiNode mergingMultiNode = (MultiNode) mergingDataValue;
existingMultiNode.setNodes(merge(mergingMultiNode.getNodes(), existingMultiNode.getNodes()));
return existingMultiNode;
}
else if(Set.class.isAssignableFrom(mergingDataValue.getClass())
&& Set.class.isAssignableFrom(existingDataValue.getClass())) {