Alright, I have had some development in http://stackoverflow.com/questions/30694560/detect-if-specific-python-app-instance-is-already-running and can prevent running multiple instances of the same app/script (by lockf), but I still need to identify which Python.app instance is running certain script. I guess it's more Cocoa-related question but I hope someone had same problem with tkinter etc.
Andrei -- https://mail.python.org/mailman/listinfo/python-list