text: var car = new Car()
  var configurator = new Configurator(car)
  
  configurator.bodyType(BodyTypes.CONVERTIBLE)
  configurator.engine(Engines.V6)
  configurator.addExtra(Extras.RADIO)
  configurator.addExtra(Extras.GPS)
  
  configurator.errors() // => {conflicts: [{ "convertible": "v6" }]}
  