On Mon, Aug 31, 2015 at 3:50 PM, Tim Peters <tim.peters@gmail.com> wrote:

But passing fold=1 in a
non-fold/gap case is almost certainly a flat-out programmer error,
_except_ that PEP 495 requires never ever complaining about it, and to
the contrary _requires_ it to be done if the user wants to find out
whether their datetime is any way odd.

A programmer who knows about fold does not need as much hand-holding as the one who does not. My customer is the ignorant programmer.

C'mon, admit it - _part_ of it makes you cringe too, if even just a little ;-)

What makes me cringe is the problem domain where I am required to implement an inverse to a non-monotonic function. And that's on top of the world where clock hands can move backwards.