Comment by aw1621107

If you're going to use the returned value you'd probably return the moral equivalent of Rust's Result/Haskell's Either/etc. types. As long as the returned types don't happen to share the necessary API(s) the type checker should yell at you if you don't branch on the returned value.

I don't think Python has the equivalent of C++'s [[nodiscard]] or Rust's #[must_use], though, so if there are cases where the return value can legitimately be ignored then return values risk missing errors that would show up under exceptions.