code: func (s *Store) getPvtDataByNumWithoutLock(blockNum uint64, filter ledger.PvtNsCollFilter) ([]*ledger.TxPvtData, error) {
  	var pvtdata []*ledger.TxPvtData
  	var err error
  	if pvtdata, err = s.pvtdataStore.GetPvtDataByBlockNum(blockNum, filter); err != nil {
  		return nil, err
  	}
  	return pvtdata, nil
  }
docs: // getPvtDataByNumWithoutLock returns only the pvt data  corresponding to the given block number.
  // This function does not acquire a readlock and it is expected that in most of the circumstances, the caller
  // possesses a read lock on `s.rwlock`