private function getPropertyNodeValue(string $key)
    {
        $data = $this->toArray();
        if (strpos($key,'/')===false){
            return $data[$key] ?? NULL;
        }
        $node_keys = explode('/', $key);
        $node = $data;
        while(($node_key = array_shift($node_keys)) && (count($node_keys) > 0)){
            if (!isset($node[$node_key])){
                return NULL;
            }
            $node = $node[$node_key];
        }
        return $node[$node_key] ?? NULL;
    }