can't add variables to instances of built-in classes

[Lawrence D’Oliveiro]

On Monday, July 18, 2016 at 3:04:13 AM UTC+12, Steven D'Aprano wrote:

> __slots__ is not obsolete, but 99% of the time you shouldn't bother with it.

I find __slots__ very useful. I have them right through my Qahirah classes <https://github.com/ldo/qahirah>, for example.