我有这样的方法:vareventNotDetected=errors.New("Eventnotdetected")typeVoucherUsageEventstruct{Mmodels.M}funcdetectVoucherUsageEvent(_uint64,changesetchangelog.Changeset)(VoucherUsageEvent,error){vareventVoucherUsageEventifchangeset.GetHeader().Table!=db.TABLE_NAME{returnevent,eventNotDetected}switchchan