why have the and in there? if a == b, then b better dxmn well == a lmao

I'm not sure who is arguing that yours is less efficient. You have a redundant equality check but that would not amount to much. Superficially, I would guess the rest is the same but in general the Python core developers tend to internally optimize for Pythonic usages so, without testing, it's hard to know whether or not there is any advantage to using the accepted solution (I would guess there's a small advantage). The accepted solution is definitely a lot more Pythonic and more maintainable though.