     override func viewDidLoad() {
         super.viewDidLoad()
         assert(assetGroup != nil, "assetGroup is nil")
-        
+
         self.title = assetGroup.groupName
         
         self.collectionView?.backgroundColor = UIColor.whiteColor()

    }
    
    override func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
        let cell = collectionView.cellForItemAtIndexPath(indexPath) as DKImageCollectionCell
        NSNotificationCenter.defaultCenter().postNotificationName(DKImageSelectedNotification, object: cell.thumbnail)
    }
    
    override func collectionView(collectionView: UICollectionView, didDeselectItemAtIndexPath indexPath: NSIndexPath) {
        let cell = collectionView.cellForItemAtIndexPath(indexPath) as DKImageCollectionCell
        NSNotificationCenter.defaultCenter().postNotificationName(DKImageUnselectedNotification, object: cell.thumbnail)
    }
}

class DKAssetsLibraryController: UITableViewController {
    weak var delegate: DKImagePickerControllerDelegate?
    
    lazy var groups: NSMutableArray = {
        return NSMutableArray()

        
        self.tableView.registerClass(UITableViewCell.self, forCellReuseIdentifier: GroupCellIdentifier)
        self.view.backgroundColor = UIColor.whiteColor()
        
        library.enumerateGroupsWithTypes(0xFFFFFFFF, usingBlock: {(group: ALAssetsGroup! , stop: UnsafeMutablePointer<ObjCBool>) in
            if group != nil {
