code: func groupDigestsByBlockNum(digests []*proto.PvtDataDigest) map[uint64][]*proto.PvtDataDigest {
  	results := make(map[uint64][]*proto.PvtDataDigest)
  	for _, dig := range digests {
  		results[dig.BlockSeq] = append(results[dig.BlockSeq], dig)
  	}
  	return results
  }
docs: // groupDigestsByBlockNum group all digest by block sequence number