My celery task is to perform an asynchronous image recognition, but after a few when I call they quote us the error, celery in combination with the Rabbitmq, celery version: 3.1

 [13:24:26 2020-06-01, 094: the ERROR/MainProcess] Unrecoverable ERROR: UnboundLocalError (" the local variable 'chunk referenced before the assignment ",) 
Traceback (the most recent call last) : 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/celery/worker/set py", line 208, in the start 
The self. The blueprint. Start (self) 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/celery/bootsteps. Py", line 127, in the start 
Step. Start (the parent) 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/celery/bootsteps. Py", line 378, in the start 
Return the self. The obj. Start () 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/celery/worker/consumer py", line 271, in the start 
The blueprint. Start (self) 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/celery/bootsteps. Py", line 127, in the start 
Step. Start (the parent) 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/celery/worker/consumer py", line 766, in the start 
C.l oop (* c.l oop_args ()) 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/celery/worker/loops. Py", line 72, in asynloop 
Next (loop) 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/kombu/async/hub. Py", line 328, in create_loop 
Next (cb) 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/celery/concurrency/asynpool py", line 186, in _recv_message 
N=len (the chunk) 
UnboundLocalError: local variable 'chunk referenced before the assignment 
[13:24:26 2020-06-01, 095: the DEBUG/MainProcess] | Worker: Closing the Hub... 
[13:24:26 2020-06-01, 095: the DEBUG/MainProcess] | Worker: Closing the Pool... 
[13:24:26 2020-06-01, 095: the DEBUG/MainProcess] | Worker: Closing Consumer... 
[13:24:26 2020-06-01, 095: the DEBUG/MainProcess] | Worker: Stopping Consumer... 
[13:24:26 2020-06-01, 095: the DEBUG/MainProcess] | Consumer: Closing the Connection... 
[13:24:26 2020-06-01, 096: the DEBUG/MainProcess] | Consumer: Closing Events... 
[13:24:26 2020-06-01, 096: the DEBUG/MainProcess] | Consumer: Closing Gossip... 
[13:24:26 2020-06-01, 096: the DEBUG/MainProcess] | Consumer: Closing Mingle... 
[13:24:26 2020-06-01, 096: the DEBUG/MainProcess] | Consumer: Closing the Control... 
[13:24:26 2020-06-01, 096: the DEBUG/MainProcess] | Consumer: Closing the Tasks... 
[13:24:26 2020-06-01, 096: the DEBUG/MainProcess] | Consumer: Closing the Heart... 
[13:24:26 2020-06-01, 096: the DEBUG/MainProcess] | Consumer: Closing the event loop... 
[13:24:26 2020-06-01, 096: the DEBUG/MainProcess] | Consumer: Stopping the event loop... 
[13:24:26 2020-06-01, 096: the DEBUG/MainProcess] | Consumer: Stopping Heart... 
[13:24:26 2020-06-01, 096: the DEBUG/MainProcess] | Consumer: Stopping the Tasks... 
[13:24:26 2020-06-01, 096: the DEBUG/MainProcess] Cancelling task consumer... 
[13:24:26 2020-06-01, 096: the DEBUG/MainProcess] | Consumer: Stopping Control... 
[13:24:26 2020-06-01, 098: the DEBUG/MainProcess] Closed channel # 3 
[13:24:26 2020-06-01, 098: the DEBUG/MainProcess] | Consumer: Stopping Mingle... 
[13:24:26 2020-06-01, 098: the DEBUG/MainProcess] | Consumer: Stopping Gossip... 
[13:24:26 2020-06-01, 103: the DEBUG/MainProcess] Closed channel # 1 
[13:24:26 2020-06-01, 103: the DEBUG/MainProcess] | Consumer: Stopping Events... 
[13:24:26 2020-06-01, 103: the DEBUG/MainProcess] Closed channel # 1 
[13:24:26 2020-06-01, 103: the DEBUG/MainProcess] | Consumer: Stopping the Connection... 
[13:24:26 2020-06-01, 103: the DEBUG/MainProcess] | Worker: Stopping the Pool... 
[13:24:26 2020-06-01, 604: the ERROR/MainProcess] ERROR while stopping the Pool: RuntimeError (' Set changed the size during iteration ',) 
Traceback (the most recent call last) : 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/celery/worker/set py", line 208, in the start 
The self. The blueprint. Start (self) 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/celery/bootsteps. Py", line 127, in the start 
Step. Start (the parent) 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/celery/bootsteps. Py", line 378, in the start 
Return the self. The obj. Start () 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/celery/worker/consumer py", line 271, in the start 
The blueprint. Start (self) 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/celery/bootsteps. Py", line 127, in the start 
Step. Start (the parent) 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/celery/worker/consumer py", line 766, in the start 
C.l oop (* c.l oop_args ()) 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/celery/worker/loops. Py", line 72, in asynloop 
Next (loop) 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/kombu/async/hub. Py", line 328, in create_loop 
Next (cb) 
The File "/home/py/./lib/python3.6 virtualenvs/ai/site - packages/celery/concurrency/asynpool py", line 186, in _recv_message 
N=len (the chunk) 
UnboundLocalError: local variable 'chunk referenced before the assignment 

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