private void addChild(Node<K, V> node, Node<K, V> child) {
if (child.getType() == NodeType.LEAF) {
LeafNode leaf = (LeafNode) child;
for (int i = 0; i < leaf.size(); i++) {
node.put((K) leaf.getKeys().get(i), (V) leaf.getValues().get(i));
}
} else if (child.getType() == NodeType.GUIDE) {
GuideNode guide = (GuideNode) child;
for (int i = 0; i < guide.size(); i++) {
addChild(node, (Node<K, V>) guide.getKids().get(i));
}
}
}
