Thanks for the kata, I learned a whole new topic and for the first time I hear about Polish notation. Interesting to know.

Please adjust the description so it is clear what exactly is expected to be a code for testing. I spent (as many other solvers here) many more minutes figuring out what is wrong with the code. While the only issue here was that you do not expect any code, just "STRANGE_STRING= ....".

Not fair, really. Description level almost as bad as daspreuße's. He is the kind of bad kata description. You may be his heir soon.

@daspreuße, man... Your katas are so badly broken. You are messy while writing instructions, your testing fails all over and specs for intended types are unclear, too. This particular kata expects us to hardcode wrong practices. I see no point doing these.

So many times I found you just copy things all over without any review or thorough revision what did you actually wrote.

From this very moment on I avoid your katas for good. It's not worth the time.

Definitely not the kata for 6 kyu. The amount of optimization it needs in order to run effectively is far beyond the beginner's knowledge of Python.
And forgive if I am wrong, english is not my native language. But I find the description for the task quite misleading. The goal in the end is to return a fraction of sum of items / number of items, not to estimate"the expected value of a random element from the matrix".

I eventually changed the code not to print but to return only and it worked. Thus the issue here is the testing algoritm expects a return value, not a terminal output.

Even for me as a newbie in coding, this code is obviously not job done good.

Finally I see an Microsoft lame coding engineer in action. Thanks for letting us know how not to patch faulty code!