python如何知道夏令时是否有效？

Question

由于某个时区中DST的开始和结束时间每年都会更改，因此python如何判断dst是否有效？

Answer 1

Actually my old answer was wrong. In the python shell you can do:

>>> import time
>>>time.localtime()
here it will show a result
>>> _.tm_isdst

This question is actually a duplicate but the old post can be found here: Python daylight savings time

Answer 2

At the very top of the CPython source code for the datetime module, it gives the source of the data:

"""Concrete date/time and related types. See http://www.iana.org/time-zones/repository/tz-link.html for time zone and DST data sources. """

Presumably this may be variable over time.