utcoffset v. _utcoffset

[Skip Montanaro]

Consider this little Python script:

import dateutil.parser
import pytz

x = dateutil.parser.parse("2013-08-16 23:00:00+01:00")
localtz = pytz.timezone("America/Chicago")
y = localtz.normalize(x)

When I execute it (Python 2.7.2, dateutil 1.5, pytz 2011h), I get this
traceback:

Traceback (most recent call last):
  File "/home/skipm/tmp/localtzex.py", line 8, in <module>
    y = localtz.normalize(x)
  File "/opt/TWWfsw/python27p/lib/python2.7/site-packages/pytz/tzinfo.py",
line 233, in normalize
    offset = dt.tzinfo._utcoffset
AttributeError: 'tzoffset' object has no attribute '_utcoffset'

Looking at the tzinfo attribute, I see that it has "utcoffset", but
not "_utcoffset".  I realize those are the latest, most up-to-datest
versions of all three elements.  I'm having trouble updating dateutil
and pytz on my Mac at home (stuck on even older versions).  Can
someone with newer versions of dateutil and pytz see if this problem
is still present?

Thx,

Skip