code: def __callback(self, event, *args, **kwargs):
          # type: (str, *Any, **Any) -> Any
          
          comp_callback = self.context.get_callback(event)
          if not comp_callback:
              # No registered callback
              return True
  
          # Call it
          result = comp_callback(self.instance, *args, **kwargs)
          if result is None:
              # Special case, if the call back returns nothing
              return True
  
          return result
docs: Calls the registered method in the component for the given event
  
          :param event: An event (IPOPO_CALLBACK_VALIDATE, ...)
          :return: The callback result, or None
          :raise Exception: Something went wrong