Scroll UICollectionView to bottom

Question

I would like to scroll the UICollectionView to the bottom so the last item is in the view. I have tried to use scrollToItemAtIndexPath but it does not seem to be working. I want

Answer 1

    lstMessages.reloadData()
    let item = self.collectionView(lstMessages, numberOfItemsInSection: 0) - 1
    let lastItemIndex = NSIndexPath(forItem: item, inSection: 0)
    lstMessages.scrollToItemAtIndexPath(lastItemIndex, atScrollPosition: UICollectionViewScrollPosition.Top, animated: false)

Where lstMessages is my collectionView