validateConcreteNode example

        $this->nodeBuilder ??= new NodeBuilder();

        return $this->nodeBuilder->setParent($this);
    }

    protected function createNode(): NodeInterface
    {
        if (!isset($this->prototype)) {
            $node = new ArrayNode($this->name, $this->parent, $this->pathSeparator);

            $this->validateConcreteNode($node);

            $node->setAddIfNotSet($this->addDefaults);

            foreach ($this->children as $child) {
                $child->parent = $node;
                $node->addChild($child->getNode());
            }
        } else {
            $node = new PrototypedArrayNode($this->name, $this->parent, $this->pathSeparator);

            $this->validatePrototypeNode($node);