问在python中需要帮助client.loop_forever()错误(mqtt-泛美卫生组织)

EN

import time

import paho.mqtt.client as paho


broker="localhost"


def on_message(client, userdata, message):
    time.sleep(1)
    print("received message =", str(message.payload.decode("utf-8")))

client = paho.Client("client-001")
client.on_message = on_message

print("connecting to broker ", broker)
client.connect(broker, port=1883)#connect
client.loop_start() #start loop to process received messages
print("subscribing ")
client.subscribe("anyisfine")#subscribe
time.sleep(2)
print("publishing ")
#client.publish("anyisfine", "on")#publish
client.publish("anyisfine", "on")#publish
time.sleep(4)
client.loop_forever()

connecting to broker  localhost
subscribing 
publishing 
received message = on
Exception in thread Thread-1:
Traceback (most recent call last):
  File "C:\Users\simba\AppData\Local\Programs\Python\Python38\lib\threading.py", line 932, in _bootstrap_inner
    self.run()
  File "C:\Users\simba\AppData\Local\Programs\Python\Python38\lib\threading.py", line 870, in run
    self._target(*self._args, **self._kwargs)
  File "C:\Users\simba\PycharmProjects\hivemqq\venv\lib\site-packages\paho\mqtt\client.py", line 3452, in _thread_main
    self.loop_forever(retry_first_connection=True)
  File "C:\Users\simba\PycharmProjects\hivemqq\venv\lib\site-packages\paho\mqtt\client.py", line 1779, in loop_forever
    rc = self.loop(timeout, max_packets)
  File "C:\Users\simba\PycharmProjects\hivemqq\venv\lib\site-packages\paho\mqtt\client.py", line 1181, in loop
    rc = self.loop_read(max_packets)
  File "C:\Users\simba\PycharmProjects\hivemqq\venv\lib\site-packages\paho\mqtt\client.py", line 1572, in loop_read
    rc = self._packet_read()
  File "C:\Users\simba\PycharmProjects\hivemqq\venv\lib\site-packages\paho\mqtt\client.py", line 2266, in _packet_read
    byte = self._sock_recv(1)
  File "C:\Users\simba\PycharmProjects\hivemqq\venv\lib\site-packages\paho\mqtt\client.py", line 664, in _sock_recv
    return self._sock.recv(bufsize)
AttributeError: 'NoneType' object has no attribute 'recv'

connecting to broker  localhost
subscribing 
publishing 
received message = on
Traceback (most recent call last):
  File "C:/Users\simba/PycharmProjects/hivemqq/main.py", line 27, in <module>
    client.loop_forever()
  File "C:\Users\simba\PycharmProjects\hivemqq\venv\lib\site-packages\paho\mqtt\client.py", line 1779, in loop_forever
    rc = self.loop(timeout, max_packets)
  File "C:\Users\simba\PycharmProjects\hivemqq\venv\lib\site-packages\paho\mqtt\client.py", line 1181, in loop
    rc = self.loop_read(max_packets)
  File "C:\Users\simba\PycharmProjects\hivemqq\venv\lib\site-packages\paho\mqtt\client.py", line 1572, in loop_read
    rc = self._packet_read()
  File "C:\Users\simba\PycharmProjects\hivemqq\venv\lib\site-packages\paho\mqtt\client.py", line 2295, in _packet_read
    data = self._sock_recv(self._in_packet['to_process'])
  File "C:\Users\simba\PycharmProjects\hivemqq\venv\lib\site-packages\paho\mqtt\client.py", line 664, in _sock_recv
    return self._sock.recv(bufsize)
AttributeError: 'NoneType' object has no attribute 'recv'

Process finished with exit code 1