Control camera zoom by pymavlink

Ground Control Software MAVLink
1

I am trying to control zoom by pymavlink
But it was failed, There is my code

    connection_string = dict_request_data['ip']
    mav = mavutil.mavlink_connection('tcp:' + connection_string)
    mav.wait_heartbeat()

    mav.mav.command_long_send(
        mav.target_system,
        mav.target_component,
        mavutil.mavlink.MAV_CMD_DO_DIGICAM_CONTROL,
        0,
        1, 3, 3, 0, 1, 0, 0)

Above code didn’t throw any excetipon, but it didn’t work too.

What’s wrong with my code?
And how i can solve this problem?