protected void composeMappingChildren(List<NodeTuple> children, MappingNode node) {
   Node itemKey = composeKeyNode(node);
   if (itemKey.getTag().equals(Tag.MERGE)) {
     node.setMerged(true);
   }
   Node itemValue = composeValueNode(node);
   children.add(new NodeTuple(itemKey, itemValue));
 }