code: func (batch *UpdateBatch) GetRangeScanIterator(ns string, startKey string, endKey string) QueryResultsIterator {
  	return newNsIterator(ns, startKey, endKey, batch)
  }
docs: // GetRangeScanIterator returns an iterator that iterates over keys of a specific namespace in sorted order
  // In other word this gives the same functionality over the contents in the `UpdateBatch` as
  // `VersionedDB.GetStateRangeScanIterator()` method gives over the contents in the statedb
  // This function can be used for querying the contents in the updateBatch before they are committed to the statedb.
  // For instance, a validator implementation can used this to verify the validity of a range query of a transaction
  // where the UpdateBatch represents the union of the modifications performed by the preceding valid transactions in the same block
  // (Assuming Group commit approach where we commit all the updates caused by a block together).