func foo(arg1: Int, arg2: Int, completionHandler: @escaping () -> ())

wrap({ foo(arg1: val1, arg2: val2, completionHandler: $0) })

Promise { foo(arg1: val1, arg2: val2, completionHandler: $0.resolve) }

Promise<Void> { foo(arg1: val1, arg2: val2, completionHandler: $0.resolve) }