code: func (l *WAL) DeleteRange(keys [][]byte, min, max int64) (int, error) {
  	if len(keys) == 0 {
  		return 0, nil
  	}
  	entry := &DeleteRangeWALEntry{
  		Keys: keys,
  		Min:  min,
  		Max:  max,
  	}
  
  	id, err := l.writeToLog(entry)
  	if err != nil {
  		return -1, err
  	}
  	return id, nil
  }
docs: // DeleteRange deletes the given keys within the given time range,
  // returning the segment ID for the operation.