addChildren(children) {
        const nodes = new TreeNodes(this._tree);

        if (isArray(this.children) || !isArrayLike(this.children)) {
            this.children = new TreeNodes(this._tree);
            this.children._context = this;
        }

        this.children.batch();
        each(children, child => {
            nodes.push(this.addChild(child));
        });
        this.children.end();

        return nodes;
    }
Add multiple children to this node.

@param {object} children Array of nodes.
@return {TreeNodes} Array of node objects.