[lucian1900]

Which PyPy does, so __slots__ is entirely useless.

[mzs]

pypy is great, but I and others used swig and am stuck now with maintaining that stuff. There is also memory benefit to slots for when there are many instances. Sometimes you just have to do gross stuff so you can get on to the next thing, it's okay when everybody understands it enough.

[lucian1900]

The memory benefit also exists on PyPy without slots.

It may be possible to write a cffi backend for swig, but it's likely quite hard.