There is nothing obvious in your code that causes the crash, making this a tough error to fix.
Start by adding an exception breakpoint to your project. When your app crashes Xcode will pause and show you the line of code where the crash.
You can also set a breakpoint at the start of the updateLocalizedTexts function, which is the function that gets called when the app finishes launching. Then you can step through the code line by line to figure out what is causing the crash. The following article should help if you have never used Xcode's debugger before:
https://www.swiftdevjournal.com/an-introduction-to-xcodes-debugger/
Topic:
Programming Languages
SubTopic:
Swift
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