def reg_on_abort(self, callable_object, *args, **kwargs):
        """ Register a function/method to be called when execution is aborted"""
        persistent = kwargs.pop('persistent', False)
        event = self._create_event(callable_object, 'abort', persistent, *args, **kwargs)
        self.abort_callbacks.append(event)
        return event
Register a function/method to be called when execution is aborted