public function build(string $identifier, callable $items): Menu
    {
        $builder = new Builder($identifier);

        $items($builder);

        if (isset($this->menus[$identifier])) {
            $this->menus[$identifier] = array_merge($this->menus[$identifier], $builder->getMenu());

            return $this;
        }

        $this->menus[$identifier] = $builder->getMenu();

        return $this;
    }