add sticky footer to UICollectionView in SWIFT

import UIKIt

class StickyFooter : UICollectionViewFlowLayout {


    var footerIsFound             : Bool = false
    var UICollectionAttributes    : [UICollectionViewLayoutAttributes]?


    override func shouldInvalidateLayoutForBoundsChange(newBounds: CGRect) -> Bool {
        return true
    }

 override func layoutAttributesForElementsInRect(rect: CGRect) -> [AnyObject]? {


     UICollectionAttributes = super.layoutAttributesForElementsInRect(rect) as? [UICollectionViewLayoutAttributes]

    for  attributes in UICollectionAttributes! {

        if let type = attributes.representedElementKind {

            if type == UICollectionElementKindSectionFooter
         {
            footerIsFound = true
            updateFooter(attributes)
         }
        }
    }

    if (!self.footerIsFound) {

            let newItem = self.layoutAttributesForSupplementaryViewOfKind(UICollectionElementKindSectionFooter, atIndexPath : NSIndexPath(index: self.UICollectionAttributes!.count))

        }

            return UICollectionAttributes
        }


    override func layoutAttributesForSupplementaryViewOfKind(elementKind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionViewLayoutAttributes! {

        let attributes = UICollectionViewLayoutAttributes(forCellWithIndexPath : indexPath)

        attributes.size = CGSizeMake(self.collectionView!.bounds.size.width, 75);

        updateFooter(attributes)

        return attributes
    }

    func updateFooter(attributes : UICollectionViewLayoutAttributes){
        let currentBounds = self.collectionView?.bounds
        attributes.zIndex = 1024
        attributes.hidden = false

        let yOffset = currentBounds!.origin.y + currentBounds!.size.height - attributes.size.height/2.0

        attributes.center = CGPointMake(CGRectGetMidX(currentBounds!), yOffset)

    }
}