This is how Python 2 did it, only with the difference that you didn't need the b prefix for ascii/byte strings. The problem was that this made a muddle of all

This is how Python 2 did it, only with the difference that you didn't need the b prefix for ascii/byte strings. The problem was that this made a muddle of all the string handling functions, which needed to be prepared to handle both types. Including ones you write yourself. And, Python being a dynamic language, getting this right was fiddly and error prone. "Forbid mixing the two" was a workable, if ergonomically annoying, in statically typed languages that predated and then subsequently had to adopt Unicode. For Python, though, it was an enormous minefield of runtime errors.