public function getByFlagLevel(int $level, int $trackableType = Tracker::TRACKER_ANY, int $perPage = 15) : LengthAwarePaginator
    {
        return $this->getModel()
                    ->newQuery()
                    ->where('level', $level)
                    ->where($this->typeClosure($trackableType))
                    ->paginate($perPage);
    }