anchor.diff:  
   commandLine.parseArgs("-a", "AES/CBC/NoPadding", "en-GB");
   assert app.locale.toLanguageTag().equals("en-GB");
  -assert app.cipher.getAlgorithm().equals("AES/CBC/NoPadding"));
  +assert app.cipher.getAlgorithm().equals("AES/CBC/NoPadding");
   ----
   
   CAUTION: _Note on subcommands:_ the specified converter will be registered with the `CommandLine` object
  
positive.code: class MyMapper implements IExitCodeExceptionMapper {
      @Override
      public int getExitCode(Throwable t) {
          if (t instance of FileNotFoundException) {
              return 74;
          }
          return 1;
  
negative.code: ----
  This produces the following usage help:
  ----
  Usage: <main class> [-l=<lang>] [-o=<option>]
    -l=<lang>     Enum values: java, groovy, kotlin, javascript, frege, clojure
    -o=<option>   Candidates: A, B, C
  ----
  