osmosis `stdout` empty on successful run. info written to `stderr`

[reneas]

I'm trying to use osmosis in a python-script and I want to log the command output in my console.

This is the function I'm using to run osmosis:

def run_subprocess(command):
    command_name = command.split()[0]  # Get the name of the command
    print(f"Running \033[1m{command_name}\033[0m with command:\n{command}\n")
    process = subprocess.Popen(
        command, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True
    )
    output, error = process.communicate()
    if output:
        print(f"\033[1m{command_name}\033[0m output:\n", output.decode())
    if error:
        print(f"\033[1m{command_name}\033[0m Error:\n", error.decode())

The command I'm inputting is:

osmosis --read-pbf /home/reneas/Dokumente/OSM/Alpentour/map_alpentour.pbf 
--node-key-value keyValueList=tourism.camp_pitch,tourism.camp_site,tourism.caravan_site
--write-xml /home/reneas/Dokumente/OSM/Alpentour/osm_raw/Camping.osm

normally communicate() returns a tuple (stdout, stderr) as is written in the description of the function but in my case even when I run the command successfully my stdout is empty and the stderr isn't.
If I do print(process.communicate()) I get:

(b'', b'Feb. 22, 2024 1:00:08 NACHM. org.openstreetmap.osmosis.core.Osmosis run\n
INFORMATION: Osmosis Version 0.48.3\n
Feb. 22, 2024 1:00:08 NACHM. org.openstreetmap.osmosis.core.Osmosis run\n
INFORMATION: Preparing pipeline.\n
Feb. 22, 2024 1:00:08 NACHM. org.openstreetmap.osmosis.core.Osmosis run\n
INFORMATION: Launching pipeline execution.\n
Feb. 22, 2024 1:00:08 NACHM. org.openstreetmap.osmosis.core.Osmosis run\n
INFORMATION: Pipeline executing, waiting for completion.\n
Feb. 22, 2024 1:00:12 NACHM. org.openstreetmap.osmosis.core.Osmosis run\n
INFORMATION: Pipeline complete.\n
Feb. 22, 2024 1:00:12 NACHM. org.openstreetmap.osmosis.core.Osmosis run\n
INFORMATION: Total execution time: 4097 milliseconds.\n')

Therefore my commandline output reads:

osmosis Error:
<rest of information herer>

is this a osmosis related issue?