BUG: wrong exception raised by Week+Day
With that fixed, we can clean up an Exception in tseries.frequencies.
Makes sense to me. Can you add a whatsnew for 1.0.0? > Verified that this will continue to work with thing like pendulum.DateTime, which is a subclass of datetime.datetime.

Is this something we need to test more generally? Probably not. Just had reports from them in the past.