Feature or enhancement

Add PEP 585 style__class_getitem__ tocsv.DictReader andcsv.DictWriter.

Pitch

With PEP 585 most generic stdlib types are now subscriptable at runtime. BothDictReader andDictWriter are generic in typeshed but don't yet implement__class_getitem__.

fromcsvimportDictWriterfromtypingimportIOdeff(fp:IO[str])->DictWriter[str]:returnDictWriter(fp, ["id","name"])

Previous discussion

• bpo-39481: PEP 585 for a variety of modules #19423
• https://mypy.readthedocs.io/en/stable/runtime_troubles.html#using-classes-that-are-generic-in-stubs-but-not-at-runtime