But that only improves on it if the other one is indeed using the same module. I won't even exclude the possibility that the other program is written in another language, like Java.

I don't want my script to overwrite another file, ever, even if the other script occasionally might overwrite one of mine. I do not want my module to get the blame with good reason. Race conditions should be excluded from my side, always, all of the time.

That limits the options a little, doesn't it?