code: function (node) {
          var originalParent = node._parent;
          if (originalParent === this) {
              return;
          }
          if (originalParent) {
              originalParent.remove(node);
          }
          node._parent = this;
          this._children.push(node);
  
          var scene = this._scene;
          if (scene && scene !== node.scene) {
              node.traverse(this._addSelfToScene, this);
          }
          // Mark children needs update transform
          // In case child are remove and added again after parent moved
          node._needsUpdateWorldTransform = true;
      }
docs: Add a child node
  @param {clay.Node} node