Generate a UUID in python but exclude specific characters

Question

I need to create a software license key generator for a client and they would like to exclude characters that resemble each other to avoid confusion in case someone decides to type theirs in. I was looking at just using the python UUID package but there doesn't seem to be an inherent way to exclude specific characters.

I was thinking of just saving it as a string and replacing any "o" character with a "%" or something. Is there a better way to do this or a reason not to do this?