
Apologies for the non-standard terminology; I'm still relatively new to the community. I meant precisely the distinction between your original proposal in <https://github.com/python/typing/discussions/1013> ("argument unions") and your updated one in the same thread ("value unions") - that is, having the type guard narrow the type of the actual value passed to the typeguard function, rather than narrowing the type of the typeguard function's argument. I hadn't seen discussion 1013 earlier, but reading the comment you link, that is indeed *exactly* what I was wanting, yes! Thanks for that! (And while I don't do a lot of exception-raising, the *Assert types in that proposal also sound quite useful to me.) My day job is already web standards work (in the W3C and JavaScript communities), so I suspect shepherding a new PEP through would be doable, but it would be a new experience for me. ^_^