You can hide the if statements with `bar = bar or Bar() `
Anyways, my point is that I can write `if X is None: X = bla` and be confident it will be correct in almost all situations. For `X = X or Y` there are some nasty corner cases where the distinction between `[]` and `""` and `{}` is somehow important, or the distinction between `is` and `==` is important, or different falsy values have different annotations attached to them, or or or....
Which is why I just do `if param is None:... ` and not worry about the few extra lines of code and move on.
The trick does have the nice property of delaying execution for evaluating what the default parameter though. The only other way to do that would involve writing lambdas which is even more code? The sibling comment suggesting a package looks like even more code to write as a user. I think any really elegant fix would have to be done in the language itself.
To me it's like complaining that (++a) is a "trick" that lets you use secret temp values that are hard to understand. I mean.. _I guess_, but it's C so it seems like the problem is that you don't like C.