Retrieving Rc Values using Dronekit problem

Hello
I am trying to extract the rc values coming from mavlink using dronekit. To test my code I am running sim_vehicle.py in one terminal, while in other I connect my script with the command --connect udp:127.0.0.1:14550.

The code is simple, I use vehicle.channels to retrieve information but all I get is None. I also tried add a message listener to get the values, but it didn’t solve either.

import time
import argparse
import dronekit

parser = argparse.ArgumentParser(description='Commands vehicle using vehicle.simple_goto.')
parser.add_argument('--connect', help="Vehicle connection target string. If not specified, SITL automatically started and used.")
args = parser.parse_args()

connection_string = args.connect


vehicle = dronekit.connect(connection_string, wait_ready=True

       
while True:
    print(vehicle.channels)
    time.sleep(2)