public static Hierarchy CreateHierarchy(this ChangeSetBuilder pendingChanges)
 {
     return pendingChanges
         .AddCommandAndPreviewTarget<Hierarchy>(new CreateHierarchyCommand());
 }
 public static Unit CreateUnit(this ChangeSetBuilder pendingChanges, string name, Address address)
 {
     return pendingChanges
         .AddCommandAndPreviewTarget<Unit>(new CreateUnitCommand(name, address));
 }