void Node::addChild(Node *child){
    CCASSERT( child != nullptr, "Argument must be non-nil");
    this->addChild(child, child->_localZOrder, child->_name);
}

void Node::addChild(Node* child, int localZOrder, const std::string &name){
    ...
    addChildHelper(child, localZOrder, INVALID_TAG, name, false);
}

void Node::addChildHelper(Node* child, int localZOrder, int tag, const std::string &name, bool setTag){
	...
    this->insertChild(child, localZOrder);
    ...
}

void Node::insertChild(Node* child, int z){
    _transformUpdated = true;
    _reorderChildDirty = true;
    _children.pushBack(child);
    child->_localZOrder = z;
}