python Generics (intermediate) anthony explains

[@sadhlife]

random trivia I learned recently: to make a generic protocol class, you can do: ``` class C(Protocol, Generic[T]): ... ``` which is a bit much, so there's a shorthand: ``` class C(Protocol[T]): ... ```

[@gabrielmota3583]

Awesome, a video about covariant/contravariant would be nice

[@AceofSpades5757]

I would also like a video on this.

[@venkateshhariharan4341]

Yes anthony that video would be great

[@AlexanderSuraphel]

@anthonywritescode this would be a great!

[@dibri]

what about it specifically? i;d love to write about it

[@sadhlife]

waiting for the 1 hour variance wideo *grabs popcorn

[@anthonywritescode]

it's not _that_ complicated -- I just didn't want to get into it in this already-long video lol

[@jbrnds]

I have a question for you, @anthonywritescode. I am in a continuous merge request review discussion back and forth with others regarding the use of `NoReturn` vs `None` for the return of a function or method that does not returns anything. Can you please shine your light on it? Docs state then the `NoReturn` is used for functions that are not expected to return anything; eg. an Exception raising function.

[@anthonywritescode]

you're in luck, I've got just the video for ya: kzbin.info/www/bejne/Y6urYaSnedmXatk

[@dhruvakashyap]

I remember my professor talking about covariate and contravariant types and all I remember is that "a bag of apples is not a bag of fruits"??

[@sadhlife]

that's actually a really good analogy XD

[@anthonywritescode]

indeed that's part of the story -- most of my framing is with c# `out` / `in` parameters (though generics are similar as well) -- immutability also comes to the table

[@veloz7860]

Is there any value in making a method generic that doesn't take any parameters, but could return a variety of things?

[@anthonywritescode]

that's not generic. a generic return value must be based on a parameter. you've got a union return (which is sort of a smell)

[@byte__3076]

If I remember correctly, you don't need necessarily to type annotate the constructor if you say so: my_object = FDict[str, int]() In this case, it makes no sense but still, you can. BTW good video, and a very interesting topic

[@anthonywritescode]

yes but generally you don't want to do that since `tp.__getitem__` is very slow and has runtime overhead

[@DavidDellsperger]

/me misreads title as "python Geriatrics (intermediate)"...don't mind me

[@akrylic_]

This is awesome