A lot of comments are about this affecting existing unmaintained code and causing problems with upgrades. But couldn’t the old code be automatically updated? E

A lot of comments are about this affecting existing unmaintained code and causing problems with upgrades. But couldn’t the old code be automatically updated? E.g. wouldn’t replacing every ‘except:’ with ‘except BaseException:’ make old codebase compatible with the proposed change? Sure, that’s a pain too and I’m not a fan of the change itself either; still, a breaking change that can be addressed automatically sounds relatively easy.