code: func NewHistoryDBProvider() *HistoryDBProvider {
  	dbPath := ledgerconfig.GetHistoryLevelDBPath()
  	logger.Debugf("constructing HistoryDBProvider dbPath=%s", dbPath)
  	dbProvider := leveldbhelper.NewProvider(&leveldbhelper.Conf{DBPath: dbPath})
  	return &HistoryDBProvider{dbProvider}
  }
docs: // NewHistoryDBProvider instantiates HistoryDBProvider