             let columnIndex  = self.longestColumnIndex()
             top = CGFloat(self.columnHeights.objectAtIndex(columnIndex).floatValue) - minimumInteritemSpacing + sectionInset.bottom
     
-            if let height = self.delegate?.colletionView?(self.collectionView!, layout: self, heightForFooterInSection: section){
+            if let height = self.delegate?.collectionView?(self.collectionView!, layout: self, heightForFooterInSection: section){
                 footerHeight = height
             }else{
                 footerHeight = self.footerHeight

        }
        return index
    }
}
    func collectionView (collectionView: UICollectionView,layout collectionViewLayout: UICollectionViewLayout,
        sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize
    
    optional func collectionView (collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout,
        heightForHeaderInSection section: NSInteger) -> CGFloat
    
    optional func collectionView (collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout,
        heightForFooterInSection section: NSInteger) -> CGFloat
    
    optional func collectionView (collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout,
        insetForSectionAtIndex section: NSInteger) -> UIEdgeInsets
    
    optional func collectionView (collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout,
        minimumInteritemSpacingForSectionAtIndex section: NSInteger) -> CGFloat
}

