anchor.diff:  This can be useful when a mixin contains logic that is common to many commands.
   For example:
   
  -[source,java]
  +.Java
  +[source,java,role="primary"]
   ----
   class AdvancedMixin {
       @Spec(Spec.Target.MIXEE) CommandSpec mixee;
  
positive.code: assert mixin.verbosity.length == 3;
  ----
  
  
  
  === Use Case: Configure Log Level with a Global Option
  
  
negative.code: }
  ----
  
  .Kotlin
  [source,kotlin,role="secondary"]
  ----
  import java.util.function.IntConsumer
  import java.util.function.IntSupplier
  // ...
  
  class AdvancedMixin {
      @Spec(Spec.Target.MIXEE)
      lateinit var mixee: CommandSpec
  
      /**
       * When the -x option is specified on any subcommand,
       * multiply its value with another integer supplied by this subcommand
       * and set the result on the top-level command.
       * @param x the value of the -x option
       */
      @Option(names = ["-x"])
      fun setValue(x: Int) {
          // get another value from the command we are mixed into
          val y = (mixee.userObject() as IntSupplier).asInt
  
          val product = x * y
  
          // set the result on the top-level (root) command
          (mixee.root().userObject() as IntConsumer).accept(product)
      }
  }
  ----
  
  ==== Accessing the Parent Command from a Mixin
  
  