Ok, so the title may trick you a bit, and I'm sorry for that but didn't find a better title.

This question might be a bit hard to understand so I'll try my best.

I have no idea how this works or if it is even possible but what I want to do is for example create a file type (lets imagine .test (in which a random file name would be random.test)). Now before I continue, its obviously easy to do this using for example:

filename = "random.test"
file = open(filename, 'w')
file.write("some text here")

But now what I would like to know is if it is possible to write the file .test so if I set it to open with a wxPython program, it recognizes it and for example opens up a Message Dialog automatically.

I'm sorry if I'm being vague and in case you don't understand, let me know so I can try my best to explain you.