anchor.diff:  
   Both the `@Option` and the `@Parameters` annotations also have a `defaultValue` attribute where a default value can be specified. This is especially useful for annotated methods. For example:
   
  +.Defining a default value using annotations
   [source,java]
   ----
   @Option(names = "-x", defaultValue = "123", paramLabel = "MULTIPLIER",
  
positive.code:         description = "${COMPLETION-CANDIDATES}, ...")
  private String algorithm = "MD5";
  ----
  Values in the `completionCandidates` list are shown as completion candidates when the user presses `[TAB]` after the `-a` option, similarly to as if the option was an `enum` type.
  
  == Groovy Scripts
  Picocli offers special support for Groovy scripts, to allow the picocli annotations to be used directly in the script without creating a class. All that is needed is to add the `@picocli.groovy.PicocliScript` annotation to the script. For example:
  
  [source,groovy, linenums]
  ----
  @Grab('info.picocli:picocli:3.9.5')
  
negative.code: 
  Subcommands can be registered declaratively with the `@Command` annotation's `subcommands` attribute, like this:
  
  .Defining subcommands declaratively with annotations
  [source,java]
  ----
  @Command(subcommands = {
  