Dart APIunself_modelActivityaccountId accountId property Null safety String accountId inherited accountId is the source node. Implementation String get accountId => throw _privateConstructorUsedError; unself_model unself_model Activity accountId property Activity class Constructors Activity fromJson Properties accountId appId archiveId copyWith created extra hashCode id labels name runtimeType source sourceId targetId timestamp type updated Methods noSuchMethod toJson toString Operators operator ==