addAll method
Implementation
void addAll(Iterable<Node> iterable) {
for (final node in iterable) {
if (children.containsKey(node.key)) throw DuplicateKeyException(node.key);
node.parent = this;
children[node.key] = node;
}
}
void addAll(Iterable<Node> iterable) {
for (final node in iterable) {
if (children.containsKey(node.key)) throw DuplicateKeyException(node.key);
node.parent = this;
children[node.key] = node;
}
}