> Ok, a couple of further (minor) issues:
> - I don't think AssertionError is the right exception type. TypeError 
> should be used when a type mismatches (e.g. "not an unicode object");
> - you don't need to check for d_type being NULL, since other methods don't;
> - if type_qualname == NULL, the original error should be retained.

Fixed.  (I suspect, though, that caching the value of __qualname__ is an unnecessary optimisation.)