if(!widget){
    widget = [[Widget alloc] initWithContext:[delegate managedObjectContext]];

    NSError* error = nil;

    if(![[widget managedObjectContext] obtainPermanentIDsForObjects:[NSArray arrayWithObject:widget] error:&error]){
        NSLog(@"%@", error);
    }
}

"The model configuration used to open the store is incompatible with the one that was used to create the store."