code: func (s *CommonStorageDB) LoadCommittedVersionsOfPubAndHashedKeys(pubKeys []*statedb.CompositeKey,
  	hashedKeys []*HashedCompositeKey) error {
  
  	bulkOptimizable, ok := s.VersionedDB.(statedb.BulkOptimizable)
  	if !ok {
  		return nil
  	}
  	// Here, hashedKeys are merged into pubKeys to get a combined set of keys for combined loading
  	for _, key := range hashedKeys {
  		ns := deriveHashedDataNs(key.Namespace, key.CollectionName)
  		// No need to check for duplicates as hashedKeys are in separate namespace
  		var keyHashStr string
  		if !s.BytesKeySupported() {
  			keyHashStr = base64.StdEncoding.EncodeToString([]byte(key.KeyHash))
  		} else {
  			keyHashStr = key.KeyHash
  		}
  		pubKeys = append(pubKeys, &statedb.CompositeKey{
  			Namespace: ns,
  			Key:       keyHashStr,
  		})
  	}
  
  	err := bulkOptimizable.LoadCommittedVersions(pubKeys)
  	if err != nil {
  		return err
  	}
  
  	return nil
  }
docs: // LoadCommittedVersionsOfPubAndHashedKeys implements corresponding function in interface DB