I am using MPMediaQuery to get all artists from library. Its returning unique names I guess but the problem is I have artists in my library like "Alice In Chains" and "Alice In Chains ". The second "Alice In Chains" has some white spaces at the end, so it returns both. I dont want that. Heres the code...

MPMediaQuery *query=[MPMediaQuery artistsQuery];
    NSArray *artists=[query collections];
    artistNames=[[NSMutableArray alloc]init];
     for(MPMediaItemCollection *collection in artists)
    {
        MPMediaItem *item=[collection representativeItem];
        [artistNames addObject:[item valueForProperty:MPMediaItemPropertyArtist]];
    }
    uniqueNames=[[NSMutableArray alloc]init];
    for(id object in artistNames)
    {
        if(![uniqueNames containsObject:object])
        {
            [uniqueNames addObject:object];
        }
    }

Any ideas?