EtcdWatchTimedOut does not been raised when occur

[TCGOGOGO]

EtcdWatchTimedOut seems raised in _wrap_request (client.py)

    def _wrap_request(payload):
        ...
                except (HTTPError, HTTPException, socket.error) as e:
                    if (isinstance(params, dict) and
                        params.get("wait") == "true" and
                        isinstance(e, ReadTimeoutError)):
                        _log.debug("Watch timed out.")
                        raise etcd.EtcdWatchTimedOut(
                            "Watch timed out: %r" % e,
                            cause=e
                        )

however, this exception will be catched internally in _acquired (lock.py)

    def _acquired(self, blocking=True, timeout=0):
        ...
            while True:
                try:
                    r = self.client.watch(watch_key, timeout=t, index=nearest.modifiedIndex + 1)
                    _log.debug("Detected variation for %s: %s", r.key, r.action)
                    return self._acquired(blocking=True, timeout=timeout)
                except etcd.EtcdKeyNotFound:
                    _log.debug("Key %s not present anymore, moving on", watch_key)
                    return self._acquired(blocking=True, timeout=timeout)
                except etcd.EtcdLockExpired as e:
                    raise e
          !!!   except etcd.EtcdException:
          !!!       _log.exception("Unexpected exception")

As a result, while loop will not break even if timeout occur. That's to say, timeout is useless