I like this code, clear and pretty. Adding some explanation of what you are doing would make it even better. More

The code is pretty enough that I can figure out why you did things, but to make the code clearer and more educational you could add some comments that explain why you do the things you do. More

This was actually the first time in my life that I saw an import inside a function, so I assumed you had some reason to do it, so I googled on possible benefits, but it seems none of them apply for this exercise. See the Stack Overflow-post about it here: https://stackoverflow.com/questions/128478/ More

This is really pretty code, and your explanation of your code is very clear. You've learned me something. More

Not the shortest code possible, but nice and clear. One small note is that you don't need isalpha(), because isupper() already ignores non-alpabet characters. I've tested it and your code works fine without it. More

Clear code needs documentation that explains what you are doing and why. Also, I personally think that list_index is a rather confusing name for a list. More

This solution is a lot clearer, thank you. More