 			if self.collectionView!.numberOfSections() > 0 {
 				for i in 0 ..< self.collectionView!.numberOfItemsInSection(0) {
 					let indexPath = NSIndexPath(forItem: i, inSection: 0)
-					attributes.append(self.layoutAttributesForItemAtIndexPath(indexPath))
+					attributes.append(self.layoutAttributesForItemAtIndexPath(indexPath)!)
 				}
 			}
 			return attributes

		self.initialize()
	}

	public required init(coder aDecoder: NSCoder) {
		super.init(coder: aDecoder)
		self.initialize()
	}


	// MARK: Readonly Properties
	/// Readonly. Index of currently selected item.
	private(set) var selectedItem: Int = 0
	/// Readonly. The point at which the origin of the content view is offset from the origin of the picker view.
	public var contentOffset: CGPoint {
		get {
