UICollectionView scroll to make section header visible

collectionViewScroll

 /**
    Scroll to make the the given section header visible.
    The function scrollToItemAtIndexPath will scroll to the item and hide the section header.
    */
    func scrollToSection(section:Int)  {
        if let cv = self.collectionView {
            let indexPath = NSIndexPath(forItem: 1, inSection: section)
            if let attributes =  cv.layoutAttributesForSupplementaryElementOfKind(UICollectionElementKindSectionHeader, atIndexPath: indexPath) {

                let topOfHeader = CGPointMake(0, attributes.frame.origin.y - cv.contentInset.top)
                cv.setContentOffset(topOfHeader, animated:true)
            }
        }
    }