ctcallcenter

I'm trying to use CTCallCenter in Swift, however it always displays error. I suppose it may cause in how to use closure but actually I don't familiar about it. Does anybody have idea to resolve this issue? Here is my code import CoreTelephony class ViewController: UIViewController{ var callCenter:CTCallCenter = CTCallCenter() override func viewDidLoad() { callCenter.callEventHandler(call:CTCall) -> Void in{ //will get CTcall status here } } } There are three errors. 1, Braced block of statements is an unused closure 2, Expected expression 3, Consecutive statements on a line must be separated