why the Publish-Subscribe can't run?

server.py:
`import asyncio
import aiozmq.rpc

class Handler(aiozmq.rpc.AttrHandler):

def __init__(self):
self.connected = False

@aiozmq.rpc.method
def remote_func(self, data: dict):
self.connected = True
print(data)

async def go():
handler = Handler()
subscriber = await aiozmq.rpc.serve_pubsub(
handler, subscribe='topic', bind='tcp://127.0.0.1:5566',
log_exceptions=True)
print("SERVE start")

while True:
await asyncio.sleep(1)

subscriber.close()
await subscriber.wait_closed()

asyncio.run(go())
`

client.py:
`import asyncio
import aiozmq.rpc

async def go():
publisher = await aiozmq.rpc.connect_pubsub(
connect='tcp://127.0.0.1:5566')
print(publisher)
await publisher.publish('topic').remote_func(2)

asyncio.run(go())
`

why can't run in python 3.8.2?
thx