For some reason, I should install Python 3.1 on my Windows XP, and I want to keep 2.5 for pywikibot. Now, I am looking for some easy and comfortable way to separate them. I mean, if I type "something.py" at the command prompt in my Pywikipedia directory, then the script should run under 2.5, and if I type this in another directory, then it should run under 3.1. Is it possible?