public optionSets: OptionSet[]  {
  return [ 
     {
         options: ['option1', 'option2'],
         runsWhen: (args) => args.options.option3 !== undefined // dependant
     },
     {
         options: ['option3', 'option4'] // will run always, default         
     },
     {
         options: ['option5', 'option6'],
         runsWhen: (args) => args.options.option5 || args.options.option6 // exclusive + optional options
     }
  ];
}