How would that work? I assume you'd still need to declare which version you want to run as, and if any library you want to import wouldnt be compatible, then ei

How would that work? I assume you'd still need to declare which version you want to run as, and if any library you want to import wouldnt be compatible, then either you are where you are right now, or it would bring a lot of backward/forward incompatibility issues with unicode/bytes/strings/syntax etc.