Error in Plex 1.1.4.1

[srijit at yahoo.com]

Hello,
I got the following error while using Plex 1.1.4.1

D:\Python24\myfiles>python plex1.py
Traceback (most recent call last):
  File "plex1.py", line 1, in ?
    from Plex import *
  File "D:\python24\lib\site-packages\Plex\__init__.py", line 34, in ?
    from Lexicons import Lexicon, State
  File "D:\python24\lib\site-packages\Plex\Lexicons.py", line 12, in ?
    import DFA
  File "D:\python24\lib\site-packages\Plex\DFA.py", line 9, in ?
    import Machines
  File "D:\python24\lib\site-packages\Plex\Machines.py", line 14, in ?
    from Transitions import TransitionMap
  File "D:\python24\lib\site-packages\Plex\Transitions.py", line 85
    def get_epsilon(self,
SyntaxError: Invalid syntax.  Assignment to None.

The corresponding source code :

#file plex1.py

from Plex import *

lexicon = Lexicon([
    (Str("Python"),      "my_favourite_language"),
    (Str("Perl"),        "the_other_language"),
    (Str("rocks"),       "is_excellent"),
    (Str("sucks"),       "is_differently_good"),
    (Rep1(Any(" \t\n")), IGNORE)
])

filename = "plex1.txt"
f = open(filename, "r")
scanner = Scanner(lexicon, f, filename)
while 1:
    token = scanner.read()
    print token
    if token[0] is None:
        break

The error was removed when I used the following code in Transitions.py

def get_epsilon(self,
    none = None):
    """
    Return the mapping for epsilon, or None.
    """
    return self.special.get('', None)


Regards,
Srijit