                     }
                 }
 
-                dispatch_async(mainQueue, { handler(mappedResponse) })
+                dispatch_async(mainQueue) { handler(mappedResponse) }
             }
             
             task.resume()

        } else {
            let userInfo = [NSLocalizedDescriptionKey: "failed to build request."]
            let error = NSError(domain: APIKitErrorDomain, code: 0, userInfo: userInfo)
            dispatch_async(mainQueue, { handler(.failure(error)) })

            return nil
        }

            task.request = Box(request)
            task.completionHandler = { data, URLResponse, connectionError in
                if let error = connectionError {
                    dispatch_async(mainQueue) { handler(.failure(error)) }
                    return
                }
                
