code: def process_external(event_name, data):
      
      for handler in find_external_handlers(event_name):
          try:
              handler(data)
          except Exception as exc:
              logger.warning(
                  (u'One of the handlers for the event "{}" has failed with the '
                   u'following exception: {}').format(event_name, str(exc)))
              if getsetting('DEBUG'):
                  raise exc
docs: Iterates over the event handler registry and execute each found
      handler.
  
      It takes the event name and its `data`, passing the return of
      data to the found handlers.