I tried to look up the discussion but didn't find much except that you flagged this as an issue. To repeat, your concern is that isdataclass() applies to *instances*, not classes, which is how Eric has designed it, but you worry that either through the name or just because people don't read the docs it will be confusing. What do you suppose we do? I think making it work for classes as well as for instances would cause another category of bugs (confusion between cases where a class is needed vs. an instance abound in other situations -- we don't want to add to that). Maybe it should raise TypeError when passed a class (unless its metaclass is a dataclass)? Maybe it should be renamed to isdataclassinstance()? That's a mouthful, but I don't know how common the need to call this is, and people who call it a lot can define their own shorter alias.

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