code: func (s *CommonStorageDB) GetPrivateDataRangeScanIterator(namespace, collection, startKey, endKey string) (statedb.ResultsIterator, error) {
  	return s.GetStateRangeScanIterator(derivePvtDataNs(namespace, collection), startKey, endKey)
  }
docs: // GetPrivateDataRangeScanIterator implements corresponding function in interface DB