public function getAllSpContainers()
    {
        $allSpContainers = [];

        foreach ($this->children as $child) {
            if ($child instanceof self) {
                $allSpContainers = array_merge($allSpContainers, $child->getAllSpContainers());
            } else {
                $allSpContainers[] = $child;
            }
        }

        return $allSpContainers;
    }