How to use NSUndoManager on macOS 10.12?

Question

I read in the documentation that NSManagedObjectContext now defaults to a nil NSUndoManager on macOS. How can I set NSUndoManager?

Answer 1

Create an undo manager and assign it to the managed object context.

NSUndoManager *undoManager = [[NSUndoManager alloc] init];
managedObjectContext.undoManager = undoManager;