Python datetime object show wrong timezone offset

Question

I am try creating a datetime object in python using datetime and pytz, the offset shown is wrong.

import datetime
from pytz import timezone

start = datetime.datetime(2011, 6, 20, 0, 0, 0, 0, timezone('Asia/Kolkata'))
print start

The output shown is

datetime.datetime(2011, 6, 20, 0, 0, tzinfo=<DstTzInfo 'Asia/Kolkata' HMT+5:53:00 STD>)

Note that 'Asia/Kolkata' is IST which is GMT+5:30 and not HMT+5:53. This is a standard linux timezone, why do I get this wrong, and how do I solve it?

Answer 1

See: http://bytes.com/topic/python/answers/676275-pytz-giving-incorrect-offset-timezone

In the comments, someone proposes to use tzinfo.localize() instead of the datetime constructor, which does the trick.

>>> tz = timezone('Asia/Kolkata')
>>> dt = tz.localize(datetime.datetime(2011, 6, 20, 0, 0, 0, 0))
>>> dt
datetime.datetime(2011, 6, 20, 0, 0, tzinfo=<DstTzInfo 'Asia/Kolkata' IST+5:30:00 STD>)

UPDATE: Actually, the official pytz website states that you should always use localize or astimezone instead of passing a timezone object to datetime.datetime.