public function fetchAll(string $group = null)
    {
        if (static::$options === null) {
            static::$options = $this
                ->createModel()
                ->when($group, function ($query, $group) {
                    return $query->where('group', $group);
                })
                ->orderBy('group', 'asc')
                ->orderBy('key', 'asc')
                ->get();
        }

        return static::$options;
    }