
Traceback (most recent call last):

 "/usr/local/Cellar/python/2.7.2/lib/python2.7/doctest.py", line 1254, in __run
compileflags, 1) in test.globs

 "<doctest chat80.doctest[26]>", line 1, in <module>
for r in rows: print "%s" % r,
TypeError: not all arguments converted during string formatting
Traceback (most recent call last):


 "/libs/celery/backends/redis.py", line 374, in on_chord_part_return

ChordError('Callback error: {0!r}'.format(exc)),


 "/libs/celery/backends/base.py", line 220, in chord_error_from_stack

return backend.fail_from_current_stack(callback.id, exc=exc)


 "/libs/celery/backends/base.py", line 227, in fail_from_current_stack

self.mark_as_failure(task_id, exc, ei.traceback)


 "/libs/celery/backends/base.py", line 155, in mark_as_failure

traceback=traceback, request=request)


 "/libs/celery/backends/base.py", line 316, in store_result

request=request, **kwargs)


 "/libs/celery/backends/base.py", line 658, in _store_result

self.set(self.get_key_for_task(task_id), self.encode(meta))


 "/libs/celery/backends/base.py", line 564, in get_key_for_task

self.task_keyprefix, key_t(task_id), key_t(key),
TypeError: sequence item 1: expected a bytes-like object, NoneType found
