Sum of all NA and empty should be 0 · Issue #18678 · pandas-dev/pandas (original) (raw)

And the prod of those should be 1.

xref: #9422, #17630, https://mail.python.org/pipermail/pandas-dev/2017-November/000657.html

We need to implement that and design and implement the alternative (either a new method, or a keyword-argument to sum and prod).