 		}
 	}
 	
-	public func useOnQueue(queue: dispatch_queue_t, closure: (directoryURL: NSURL) -> Void) {
+	public func useOnQueue(queue: dispatch_queue_t, closure: (directoryURL: NSURL) -> ()) {
 		dispatch_group_notify(group, queue) {
 			if let createdDirectoryURL = self.createdDirectoryURL {
 				closure(directoryURL: createdDirectoryURL)

				// Convert components back into a URL.
				guard let directoryURL = NSURL.fileURLWithPathComponents(pathComponents) else { return }
				
				try fm.createDirectoryAtURL(directoryURL, withIntermediateDirectories:true, attributes:nil)
				
				self.createdDirectoryURL = directoryURL
			}

		createDirectory()
	}
	
	private func createDirectory() {
		let queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0)
		dispatch_group_async(group, queue) {
			let fm = NSFileManager.defaultManager()
			
			do {
				let baseDirectoryURL = try fm.URLForDirectory(self.directoryBase, inDomain: self.domainMask, appropriateForURL: nil, create: true)
				
				// Convert path to its components, so we can add more components
				// and convert back into a URL.
