anchor.diff:  
   Type converters declared with the `converter` attribute need to have a public no-argument constructor to be instantiated, unless a <<Custom Factory>> is installed to instantiate classes.
   
  -CAUTION: If your type converter is declared as nested class, make sure you mark this class as `static`, or picocli will not be able to instantiate your nested converter class without a <<Custom Factory>>.
  +CAUTION: If your type converter is declared as nested class, make sure you mark this class as `static`, or picocli will not be able to instantiate your nested converter class.
   
   === Arrays, Collections, Maps
   NOTE: Starting from picocli 2.0, the `type` attribute is no longer necessary for `Collection` and `Map` fields:
  
positive.code: 
  All transformers are called once, after the full command hierarchy is constructed, and before any command line arguments are parsed.
  
  CAUTION: If your model transformer is declared as nested class, make sure you mark this class as `static`, or picocli will not be able to instantiate your transformer class without a <<Custom Factory>>.
  
  === Automatic Parameter Indexes
  ==== Automatic Indexes
  
negative.code: 
  See the sections on <<Custom Parameter Processing>> for more details.
  
  CAUTION: Make sure any nested classes are `static`, or picocli will not be able to instantiate them.
  
  === Handling Invalid Input
  
  