If you add the return statement mentioned below, then I *think* this should be able to look like:

```py
def _restart(self):
    """If this async is executing, immediately cease execution and reinsert this job."""
    logging.info("Async job was aborted and restarted: %r", restart)

    if not self._executing:
        raise NotExecutingError("Must be executing to restart the job, "
                                "perhaps you want Async.start().")

    # Reset executing flag so we can restart.
    self._executing = False

    # Restart the async.
    return self.start()
```