Cinnamon renice on launch

Question

I installed Ubuntu and changed shell to Cinnamon. Is there any possible way to renice on launch Cinnamon to, let's say, -19?

I tried to change /usr/bin/cinnamon_launcher like this, but it doesn't help:

cinnamon_pid = os.fork()
if cinnamon_pid == 0:
    os.execvp("cinnamon", ("cinnamon", "--replace", ) + tuple(sys.argv[1:]))
    Popen(["nice"], preexec_fn=lambda : os.nice(-19))

Thanks on your help!