On Tue, Aug 25, 2015 at 5:28 PM, Carl Meyer <carl@oddbird.net> wrote:
>
> My answer is "only in those same locations where the fold attribute
> would otherwise be checked in order to resolve an ambiguity."


This includes utcoffset() which is used in datetime.__eq__.  What should __eq__ do if utcoffset() raises AmbiguousTimeError?  Unpatched, it will propagate the exception resulting in for example x in [y, x, x, x] raising an error whenever y happened to be fold=-1 ambiguous.  Is your code prepared to handle  AmbiguousTimeError whenever you search for a date in a list?  Does it check for fold != -1 before adding a date to a list?