code: func (historyDB *historyDB) GetLastSavepoint() (*version.Height, error) {
  	versionBytes, err := historyDB.db.Get(savePointKey)
  	if err != nil || versionBytes == nil {
  		return nil, err
  	}
  	height, _ := version.NewHeightFromBytes(versionBytes)
  	return height, nil
  }
docs: // GetBlockNumFromSavepoint implements method in HistoryDB interface