public function addChild(string $title, string $url = '', array $children = [], array $fields = []): Builder
    {
        // Get last item index
        $index = count($this->menu) - 1;

        if ($index < 0) {
            return $this;
        }

        $this->menu[$index]->appendChild($this->parseMenuItems($title, $url, $children, $fields));

        return $this;
    }