On 2/11/21 9:51 PM, Guido van Rossum wrote:
> On Thu, Feb 11, 2021 at 9:13 PM Paul Bryan <pbryan@anode.ca
> <mailto:pbryan@anode.ca>> wrote:
>     1. I understand your rationale for not using Optional; however, I am
>     concerned about the potential for confusion in a world where there
>     is both an Optional[...] and Required[...] type hint. Also, the
>     potential for an ugly (but valid?!) Required[Optional[...]] construct.
>
>
> To reduce confusion we can recommend T|None over Optional[T].

I do in fact make that recommendation for Python 3.10. See §"How to
Teach This".

But I also have a related open issue in §"Open Issues" that ponders what
can be done in Python 3.9 and lower, where the T|None syntax isn't
available. Maybe:

Yes (Python 3.5 - 3.9):
        Required[Union[..., None]]

Avoid:
        Required[Optional[...]]