Python and timezones

[shandy.b]

I'm trying to write some code to deal with world timezones, and I'm
getting a strange result. America/Iqaluit should not be showing up in
UTC+00:00, but it is. Can anyone see what's wrong with this code?
import time
from datetime import datetime
import os
import pytz

def getZoneNamesOnThisComputer():
for i in pytz.all_timezones:
if os.path.exists( os.path.join('/tmp/usr/share/zoneinfo/',
i)):
yield i
def getZonesGroupedByOffset():
'''return a dict of all the zone names , grouped by their offset
eg:
{'-0400': ['America/Blanc-Sablon', 'Etc/GMT+4'],
'+0000': ['America/Iqaluit', 'Etc/GMT', 'Europe/Belfast', 'GB',
'GMT'],
...
}
'''
Y,M,D,h,m,s = time.localtime()[:6]

zonesGroupedByOffset = {}

for name in getZoneNamesOnThisComputer():
tz = pytz.timezone(name)
now = datetime(Y,M,D,h,m,s, tzinfo=tz)
# strfime returns a string like "-0800" or "+0430" or "0000"
offsetKey = now.strftime('%z')
if not zonesGroupedByOffset.has_key(offsetKey):
zonesGroupedByOffset[offsetKey] = []
zonesGroupedByOffset[offsetKey].append(name)
return zonesGroupedByOffset
z = getZonesGroupedByOffset()
print z['+0000']

# Why is America/Iqaluit showing up here???