Failed to start cloudtunes-worker [AttributeError: 'NoneType' object has no attribute 'on_soft_timeout']

[hysci]

I used the docker mode to start cloudtunes-server. The following things went OK
supervisord
redis-server
mongdb
Except cloudtunes-worker.
The error messages were as follows:

2017-04-18T07:28:57.650+0000 [initandlisten] connection accepted from 127.0.0.1:44944 #2 (1 connection now open)
/usr/local/lib/python2.7/dist-packages/celery/apps/worker.py:169: RuntimeWarning: Running celeryd with superuser privileges is discouraged!
'Running celeryd with superuser privileges is discouraged!'))

-------------- celery@4b460f042a3a v3.0.11 (Chiastic Slide)
---- **** -----
--- * *** * -- [Configuration]
-- * - **** --- . broker: redis://localhost:6379/1

• ** ---------- . app: tasks:0x7fa7f774b390
• ** ---------- . concurrency: 20 (processes)
• ** ---------- . events: OFF (enable -E to monitor this worker)
• ** ----------
• *** --- * --- [Queues]
  -- ******* ---- . celery: exchange:celery(direct) binding:celery
  --- ***** -----

[2017-04-18 07:28:57,786: ERROR/MainProcess] Unrecoverable error: AttributeError("'NoneType' object has no attribute 'on_soft_timeout'",)
Traceback (most recent call last):
File "/usr/local/lib/python2.7/dist-packages/celery/worker/init.py", line 347, in start
component.start()
File "/usr/local/lib/python2.7/dist-packages/celery/concurrency/base.py", line 111, in start
self.on_start()
File "/usr/local/lib/python2.7/dist-packages/celery/concurrency/processes/init.py", line 79, in on_start
self.on_soft_timeout = P._timeout_handler.on_soft_timeout
AttributeError: 'NoneType' object has no attribute 'on_soft_timeout'