Steven, Sorry for not replying to your message due to my mailing list incompetence (configured for digest at first). I am replying to your message here: https://mail.python.org/pipermail/python-ideas/2017-September/047239.html I have not figured out the issue with readline/arrow keys on the overridden files. Consider this current iteration an RFC on the concept. I’m sure there are bugs in there. ☺ wt