code: func (db *BytesConnectionEtcd) ListValuesRange(fromPrefix string, toPrefix string) (keyval.BytesKeyValIterator, error) {
  	return listValuesRangeInternal(db.Logger, db.etcdClient, db.opTimeout, fromPrefix, toPrefix)
  }
docs: // ListValuesRange returns an iterator that enables traversing values stored
  // under the keys from a given range.