diff --git a/crans_utils.py b/crans_utils.py
index 6317907..ac0e78d 100644
--- a/crans_utils.py
+++ b/crans_utils.py
@@ -352,8 +352,7 @@ def datetime_from_generalized_time_format(gtf):
         tz = '+0000'
     the_date = datetime.datetime.strptime(date, "%Y%m%d%H%M%S")
     if pytz is not None:
-        tz_dict = build_tz_dict()
-        the_timezone = tz_dict.get(tz, pytz.utc)
+        the_timezone = pytz.FixedOffset(int(tz[0:-2])*60 + int(tz[-2:]))
         the_date = the_timezone.localize(the_date)
         the_date = the_timezone.normalize(the_date)
     return the_date
@@ -364,27 +363,7 @@ def datetime_to_generalized_time_format(datetime_obj):
     if datetime_obj.utcoffset() is None:
         if pytz is not None:
             datetime_obj = pytz.utc.localize(datetime_obj)
-            datetime_obj = pytz.utc.normalize(datetime_obj)
         else:
             to_append = "Z"
     mostly_gtf = datetime.datetime.strftime(datetime_obj, "%Y%m%d%H%M%S%z")
     return mostly_gtf.replace('+0000', "Z") + to_append
-
-def build_tz_dict():
-    """Crappy way to define a dict containing all timezones that
-    pytz can handle.
-
-    It seems there is no way to get a tz object from the offset
-    with pytz.
-
-    """
-    tz_dict = {}
-    for tz in pytz.common_timezones:
-        mytz = pytz.timezone(tz)
-        d = datetime.datetime.now(mytz).utcoffset().total_seconds()
-        hours = int(d)/3600
-        minutes = int(float(int(d) % 3600)/60)
-        fmt = "%+03d%02d" % (hours, minutes)
-        if fmt not in tz_dict:
-            tz_dict[fmt] = mytz
-    return tz_dict