on running celery -A proj worker throws this error

[2018-11-15 12:02:53,607: CRITICAL/MainProcess] Unrecoverable error: AttributeError("'float' object has no attribute 'items'",)
Traceback (most recent call last):
File "/user/lib/python3.6/site-packages/celery/worker/worker.py", line 205, in start
self.blueprint.start(self)
File "/user/lib/python3.6/site-packages/celery/bootsteps.py", line 119, in start
step.start(parent)
File "/user/lib/python3.6/site-packages/celery/bootsteps.py", line 369, in start
return self.obj.start()
File "/user/lib/python3.6/site-packages/celery/worker/consumer/consumer.py", line 317, in start
blueprint.start(self)
File "/user/lib/python3.6/site-packages/celery/bootsteps.py", line 119, in start
step.start(parent)
File "/user/lib/python3.6/site-packages/celery/worker/consumer/consumer.py", line 593, in start
c.loop(*c.loop_args())
File "/user/lib/python3.6/site-packages/celery/worker/loops.py", line 91, in asynloop
next(loop)
File "/user/lib/python3.6/site-packages/kombu/asynchronous/hub.py", line 354, in create_loop
cb(*cbargs)
File "/user/lib/python3.6/site-packages/kombu/transport/redis.py", line 1040, in on_readable
self.cycle.on_readable(fileno)
File "/user/lib/python3.6/site-packages/kombu/transport/redis.py", line 337, in on_readable
chan.handlerstype
File "/user/lib/python3.6/site-packages/kombu/transport/redis.py", line 724, in _brpop_read
self.connection._deliver(loads(bytes_to_str(item)), dest)
File "/user/lib/python3.6/site-packages/kombu/transport/virtual/base.py", line 983, in _deliver
callback(message)
File "/user/lib/python3.6/site-packages/kombu/transport/virtual/base.py", line 632, in _callback
self.qos.append(message, message.delivery_tag)
File "/user/lib/python3.6/site-packages/kombu/transport/redis.py", line 149, in append
pipe.zadd(self.unacked_index_key, time(), delivery_tag)
File "/user/lib/python3.6/site-packages/redis/client.py", line 2263, in zadd
for pair in iteritems(mapping):
File "/user/lib/python3.6/site-packages/redis/_compat.py", line 123, in iteritems
return iter(x.items())
AttributeError: 'float' object has no attribute 'items'

Using Python 3.6.6, redis 3.0.0.post1