public function value(string $category_key, string $config_key)
    {
        if (!($category = ConfigCategory::where('key', $category_key)->first())) {
            throw new \Exception("Category with name ($category_key) not found");
        }
        if (!($config = $category->configs()->where('key', $config_key)->first())) {
            throw new \Exception("Config with name ($config_key) not found");
        }
        return $config->value;
    }