How to send command to via zmq?

ChirpStack Concentratord
1

import time
import zmq
context = zmq.Context()
socket = context.socket(zmq.REQ)
socket.connect(“ipc:///tmp/concentratord_command”)

for request in range(10):
print(“Sending request %s …” % request)
socket.send(b"gateway_id")

#  Get the reply.
message = socket.recv()

as I send the command “gateway_id” I have the gateway ID as the reply, but I got nothing.
What is the right way to read anything from the server using by the concentratord?