code: func (tx *Tx) AscendRange(index, greaterOrEqual, lessThan string,
  	iterator func(key, value string) bool) error {
  	return tx.scan(
  		false, true, true, index, greaterOrEqual, lessThan, iterator,
  	)
  }
docs: // AscendRange calls the iterator for every item in the database within
  // the range [greaterOrEqual, lessThan), until iterator returns false.
  // When an index is provided, the results will be ordered by the item values
  // as specified by the less() function of the defined index.
  // When an index is not provided, the results will be ordered by the item key.
  // An invalid index will return an error.