New to python/coding Need help on Understanding why this code isn't working. Thanks!

[mat3372]

So, this is not error (i.e. when you run the code), nor it comes from the interpreter. It's a warning from your IDE about using mutable default argument. Read why it may surprise you
https://docs.python-guide.org/writing/go...-arguments

Thanks for all your help!!! When I run the code "as is" nothing happens. Not totally true my interpreter(Anaconda-VS Code) lists the file that im working in but doesn't list alphabetized names. I don't know why they would put that in the book if it is the wrong way of doing it. So confusing. I read the info in the link you provided and im going to try and do it the way it lists. Thanks again for all your help. I am really green at all this and just trying to make sense of it all.