Python spawn detatched non-python process on linux?

I was to make a launcher application, I haven't found a way to detach a sub-process entirely from the spawning python process.

When I launch a program with my desktop's (cinnamon's) launcher the process tree goes:

/sbin/init -> mdm -> mdm -> cinnamon-session -> cinnamon -> the-app-i-launched

Of the threads I read, this one was the most insightful/helpful: Launch a completely independent process. But gets muddied answers as the OP is looking to run python code, which can often be achieved in many usually-preferred ways than by spawning an independent process.

From other posts from stack overflow that do not answer how to launch a detatched python process:

• Running daemonalized python code: Applicable to running python code/module as a daemon, (not another process/application) detached from the python instance.
• subprocess.call: Process spawns as a child of the python process.
• os.system: Process spawns as a child of the python process.
• close_fds: (Apparently) Windows(R)-only solution, need portable solution (primary target is Debian linux). Attempting to use close_fds=True on linux, process spawns as a child of the python process.
• creationflags: Windows(R)-only solution. On linux raises: ValueError: creationflags is only supported on Windows platforms.
• prefix launched process with nohup: Process spawns as a child of the python process. As far as I know, nohup or equivalent is not available on all platforms, making it a linux-only solution.
• os.fork: Same as "Running daemonalized python code".
• multiprocessing: Same problem as "Running daemonalized python code": useful only for running python code/module.
• os.spawnl* + os.P_NOWAIT: Deprecated functions are undesirable to use for new code. In my testing I was not able to see my process actually spawned at all.
• os.spawnl* + os.P_DETACH: Windows(R)-only, seemingly removed in current python 2.X versions: AttributeError: 'module' object has no attribute 'P_DETACH'.
• os.system + shell fork: I was able to actually see my process run detatched from the python process with this, however I am woried that it has the faults:
  • Relies on running commands in a shell, which is more vulnerable to maliciousness, intentional or otherwise^?.
  • Relies on non-portable^? POSIX/shell^? syntaxies that may not be interpenetrate on non-Linux platforms. Which I haven't dug up any good reference for portability on ^{Partial Ref}.
• subprocess.Popen ^Alt: I still only observed the sub-process running as a child of the python process.

A working solution can be found in JonMc's answer here. I use it to open documents using 'xdg-open'.

You can change the stderr argument to stderr=open('/dev/null', 'w'), if you do not want a logfile.