Core Data error

gistfile1.m

#pragma mark - validation

- (BOOL)validateForInsert:(NSError *__autoreleasing *)error {
    NSMutableDictionary *userInfo = [[NSMutableDictionary alloc] init];
    [userInfo setObject:@"Cannot add more than 10 moves" forKey:NSLocalizedFailureReasonErrorKey];
    [userInfo setObject:self forKey:NSValidationObjectErrorKey];
    
    NSError *tooManyMovesError = [NSError errorWithDomain:@"TenMovesDomain" code:NSManagedObjectValidationError userInfo:userInfo];
    
    if (*error == nil) {
        *error = tooManyMovesError;
    } else {
        *error = [NSError errorFromOriginalError:*error error:tooManyMovesError];
    }
    
    return NO;
}