Thread 1: "Attempted to scroll the collection view to an out-of-bounds item (0) when there are only 0 items in section 0. Collection view: <UICollectionView: 0x13f836200; frame = (0 158.667; 390 651.333); clipsToBounds = YES; autoresize = RM+BM; gestureRecognizers = <NSArray: 0x28389a3d0>; layer = <CALayer: 0x2836d5940>; contentOffset: {0, 0}; contentSize: {390, 20}; adjustedContentInset: {0, 0, 0, 0}; layout: <UICollectionViewFlowLayout: 0x13f043cb0>; dataSource: <iKids.SerialViewController: 0x13f110b50>>."