Nested Closures in Swift 2.1
问题 I want to clear about Nested Closures in Swift 2.1 Here I declare a nested closure, typealias nestedDownload = (FirstItem: String!)-> (SencondItem: String!)->Void Then I use this nestedDownload closure as a parameter of the following function and try to complete the compliletion parameter value in function like as func nestedDownloadCheck(compliletion:nestedDownload){ compliletion(FirstItem: "firstItem") } But this says the error, " Expression resolves to an unused function " Also , when I