[Autonomous BlueROV2] MavLink/Ardusub help

Hi,
I was reading and I would like do something similar.
I want start to run this script directly in the RPi from the BlueROV2, without lose the telemetry and video in QGC.
But when I do, the script remains frozen and only I see this result:

"
pi@raspberrypi:~ $ python test_auv.py
Waiting for APM heartbeat
"

The script to split the telemetry is for default:

"
# this starts mavproxy so that the serial link to the companion computer (on /dev/ttyACM0)
# is available to a companion computer and external GCSs via UDP. This broadcasts so that
# multiple IP addresses can receive the telemetry.

# For PixHawk or other connected via USB on Raspberry Pi
cd /home/pi
mavproxy.py --master=/dev/serial/by-id/usb-3D_Robotics_PX4_FMU_v2.x_0-if00,115200
–source-system=200
–cmd=“set heartbeat 0”
–out udpin:localhost:9000
–out udpbcast:192.168.2.255:14550
"

I try change in my code of ‘test mavlink messages’ with:
master = mavutil.mavlink_connection(‘udp:localhost:14550’)
or
master = mavutil.mavlink_connection(‘udp:192.168.2.1:14550’)
or
master = mavutil.mavlink_connection(‘udp:192.168.2.2:14550’)
or
master = mavutil.mavlink_connection(‘udp:localhost:9000’)

But, none works.
Can you help me please?
Thanks a lot!
Greetings!