protected function adminGroup(Closure $callback)
    {
        $attributes = $this->getAdminAttributes();

        $this->prefix(Arr::get($attributes, 'prefix', 'dashboard'))
             ->name(Arr::get($attributes, 'name', 'admin::'))
             ->namespace($this->adminNamespace)
             ->middleware(Arr::get($attributes, 'middleware', ['web', 'auth', 'admin']))
             ->group($callback);
    }