I am keen to start your tutorial on Reactive Programming with Swift (and hope to learn as much as I did from Swift Apprentice, thank you!)
Following tutorial recommendations on pages 120-121 I created a copy of RxPlayground in /Users/gs/RxSwift-02-starter/. When I ran ./bootstrap.sh, Xcode launched successfully and seemed to create the .xcworkspace file. But warnings from Xcode when I built it have stopped me going further.
Xcode (10.2.1) issued 12 warnings. I resolved 3 deprecated Swift code warnings but there are 3 more warnings I don’t understand.
 call to a never-returning function (7 times)
A call to a never-returning function
- Will never be executed*
 SwiftLint is not installed (once)
Custom shell script SwiftLint runs for 0.1 seconds. The first two commands that appear to use different paths
PhaseScriptExecution SwiftLint /Users/gs/Library/Developer/Xcode/DerivedData/RxSwiftPlayground-hhefrghxicxgokdfidtofqjpnqem/Build/Intermediates.noindex/Rx.build/Debug/RxSwift.build/Script-A21F589121E109AD0051AEA2.sh (in target: RxSwift)
 ‘Hashable.hashValue’ is deprecated (once)
*'Hashable.hashValue' is deprecated as a protocol requirement; conform type 'BagKey' to 'Hashable' by implementing 'hash(into:)' instead*
I should also mention I that recently upgraded MacOS to 10.15 Beta just before starting these tutorials. Will I need to be use a later edition of this tutorial ? what do I need to do to get rid of these warnings ?