Error subclassing datetime.date and pickling

[Mike Rooney]

Hi everyone, this is my first post to this list. I am trying to create a 
subclass of datetime.date and pickle it, but I get errors on loading it 
back. I have created a VERY simple demo of this:

import datetime

class MyDate(datetime.date):
    """
    This should be pickleable.
   
    >>> md = MyDate(2007, 1, 6)
    >>> import pickle
    >>> pickle.dump(md, open("test.pickle", 'w'))
    >>> mdp = pickle.load(open("test.pickle"))
    >>> import os; os.remove("test.pickle")
    """
    def __init__(self, y, m, d):
        datetime.date.__init__(self, y, m, d)
       
if __name__ == "__main__":
    import doctest
    doctest.testmod()


The traceback that occurs is:

    Traceback (most recent call last):
      File "C:\Python25\lib\doctest.py", line 1212, in __run
        compileflags, 1) in test.globs
      File "<doctest __main__.MyDate[3]>", line 1, in <module>
        mdp = pickle.load(open("test.pickle"))
      File "C:\Python25\lib\pickle.py", line 1370, in load
        return Unpickler(file).load()
      File "C:\Python25\lib\pickle.py", line 858, in load
        dispatch[key](self)
      File "C:\Python25\lib\pickle.py", line 1133, in load_red
        value = func(*args)
    TypeError: __init__() takes exactly 4 arguments (2 given)


I have found a few relating issues:
 - 
https://sourceforge.net/tracker/?func=detail&atid=105470&aid=952807&group_id=5470
 - 
http://sourceforge.net/tracker/index.php?func=detail&aid=720908&group_id=5470&atid=105470

But these are both rather old and are marked as fixed. I am running 
Python 2.5.1 on Windows XP SP2. Any help here would be greatly appreciated!

- Mike