public static function gets($keys = null)
    {
        $noInitModel = static::buildNoInitModel();
        $query = static::find();
        if ($keys == null) {
            $models = $query->all();
        } elseif (is_array($keys)) {
            $array = [];
            foreach ($keys as $key) {
                if (is_string($key) && strlen($key)) {
                    $array[] = $key;
                }
            }
            $models = $query->where([$noInitModel->idAttribute => $array])->all();
        }
        $result = [];
        foreach ($models as $key => $model) {
            $result[$model->key] = $model->value;
        }
        return $result;
    }