code: def iso_register(iso_code):
      
      def wrapper(cls):
          registry.register(iso_code, cls)
          return cls
      return wrapper
docs: Registers Calendar class as country or region in IsoRegistry.
  
      Registered country must set class variables ``iso`` using this decorator.
  
      >>> from workalendar.core import Calendar
      >>> @iso_register('MC-MR')
      >>> class MyRegion(Calendar):
      >>>     'My Region'
  
      Region calendar is then retrievable from registry:
  
      >>> calendar = registry.get_calendar_class('MC-MR')