Please update your this tutorial https://github.com/codepath/ios_guides/wiki/Multithreading-in-iOS for swift 4.1 where it give the error "dispatch_group_t' has been explicitly marked unavailable here (Dispatch.dispatch_group_t)". Change tutorial with DispatchQueue instead.
Please update your this tutorial https://github.com/codepath/ios_guides/wiki/Multithreading-in-iOS for swift 4.1 where it give the error "dispatch_group_t' has been explicitly marked unavailable here (Dispatch.dispatch_group_t)". Change tutorial with DispatchQueue instead.