code: def next_on(context, rrevent=None):
      
      request = context['request']
      if rrevent is None:
          rrevent = context.get('page')
      eventNextOn = getattr(rrevent, '_nextOn', lambda _:None)
      return eventNextOn(request)
docs: Displays when the next occurence of a recurring event will be.  If the
      recurring event is not specified it is assumed to be the current page.