protected function sortTree($node1, $node2)
    {
        $order1 = $node1['node']['order'];
        $order2 = $node2['node']['order'];

        if ($order1 == $order2 || $order1 == -1 || $order2 == -1) {
            return 0;
        }

        return ($order1 < $order2) ? -1 : 1;
    }
protected function sortTree($node1, $node2)
    {
        $order1 = $node1['node']['order'];
        $order2 = $node2['node']['order'];

        if ($order1 == $order2 || $order1 == -1 || $order2 == -1) {
            return 0;
        }

        return ($order1 < $order2) ? -1 : 1;
    }
@param ReadNodeInterface $node1
@param ReadNodeInterface $node2

@return int