timezone('US/Eastern') >>> eastern.localize(datetime(2002, 10, 27, 1, 30, 0), is_dst=False) datetime.datetime( 2002, 10, 27, 1, 30, tzinfo=<DstTzInfo 'US/Eastern' EST-1 day, 19:00:00 STD>) >>> eastern.localize(datetime(2002, 10, 27, 1, 30, 0), is_dst=True) datetime.datetime( 2002, 10, 27, 1, 30, tzinfo=<DstTzInfo 'US/Eastern' EDT-1 day, 20:00:00 DST>)