TGRTweet.m

+ (id)lastTweetInManagedObjectContext:(NSManagedObjectContext *)context
{
    NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"identifier"
                                                                     ascending:NO];
    
    NSFetchRequest *fetchRequest = [self fetchRequest];
    [fetchRequest setSortDescriptors:@[sortDescriptor]];
    [fetchRequest setFetchLimit:1];
    
    return [[context executeFetchRequest:fetchRequest error:NULL] lastObject];
}