Episode information of not available

Hi there,

I was looking if I could retreive episode information through imdbpy,
but was unable to do so:

I executed following code which can be found here:
http://imdbpy.sourceforge.net/docs/README.series.txt

  from imdb import IMDb
  i = IMDb()
  m = i.get_movie('0389564')  # The 4400.
  m['kind']    # kind is 'tv series'.
  i.update(m, 'episodes')   # retrieves episodes information.

 Whenever I call:
 m['episodes']

I get following error message:

...\imdb\utils.pyc in __getitem__(self, key)
   1431         # Handle key aliases.

   1432         key = self.keys_alias.get(key, key)
-> 1433         rawData = self.data[key]
   1434         if key in self.keys_tomodify and \
   1435                 self.modFunct not in (None, modNull):

KeyError: 'episodes'

I'm I doing something wrong? I currently using IMDbPY 4.8.2 2011-11-01