Python's mistake is not including a default-coding-style formatting system with the language (or if it does, making it so obscure I don't know about it).

The formatter should ALSO, when cleaning up the code, see if it compiles with four spaces equal to a tab, and then if not, if eight spaces is a tab.

I'd prefer that levels of intent be a tab (not space; if you're going to make presentation of indent important make it something the client CAN modify without changing the meaning of the code).