python timezone information error

python_logging_test

#!/usr/bin/env python
import os
import time

# The following is a file in /usr/share/zoneinfo
os.environ["TZ"] = "Europe/Rome"
time.tzset()

import sys
print sys.version_info
import commands
print "System time: %s" % commands.getoutput("date --rfc-3339=seconds")

import logging
import datetime
logging.basicConfig(level=logging.DEBUG, stream=sys.stdout,
                        format="%(asctime)s:" + logging.BASIC_FORMAT,
                         datefmt="%Y-%m-%dT%H:%M:%S%z")

logger = logging.getLogger()
logger.info("Something happened")

Verified that /usr/share/zoneinfo/Europe/Rome exists.

Output on Ubuntu Xenial:

sys.version_info(major=2, minor=7, micro=12, releaselevel='final', serial=0)
System time: 2017-05-22 11:25:36+02:00
2017-05-22T11:25:36+0000:INFO:root:Something happened

Output on Ubuntu Trusty:

sys.version_info(major=2, minor=7, micro=6, releaselevel='final', serial=0)
System time: 2017-05-22 11:29:34+02:00
2017-05-22T11:29:34+0000:INFO:root:Something happened