partial void DeleteHomework(Homework instance);
 partial void UpdateHomework(Homework instance);
 private void detach_Homeworks(Homework entity)
 {
     this.SendPropertyChanging();
     entity.Class1 = null;
 }
 partial void InsertHomework(Homework instance);
 private void attach_Homeworks(Homework entity)
 {
     this.SendPropertyChanging();
     entity.Class1 = this;
 }