On Fri, Aug 28, 2015 at 4:58 PM, Alexander Belopolsky <alexander.belopolsky@gmail.com> wrote:

On Fri, Aug 28, 2015 at 7:51 PM, Guido van Rossum <guido@python.org> wrote:
On Fri, Aug 28, 2015 at 6:53 PM, Guido van Rossum <guido@python.org> wrote:
I'm not entirely sure why we didn't add this to the stdlib ages ago.

But (as my base class shows) implementing the required API using only the tm_isdst flag and the timezone-related attributes of the time module (tzname, timezone, altzone) a satisfactory implementation can be obtained, and that API has been stable since the beginning of time.

To be fair, we did ship something very similar, but it was only accessible to users who read the library manual: <https://hg.python.org/cpython/file/v3.5.0rc2/Doc/includes/tzinfo-examples.py#l54>. :-)

So, again, why have we been shy of adding this to the stdlib? We did (eventually) add the fixed offset classes. (And before you say "for the same reason we didn't add the USTimeZone class", the reasons can't be the same -- the latter would require maintenance whenever the US changes its DST rules, while LocalTime is oblivious to all that.)

--Guido van Rossum (python.org/~guido)