pickle.dump meet RuntimeError: maximum recursion d

I have noticed that it may be caused by beautifulsoup or recursive data structure. however, the data structure that cause error seems no problem:

class Movie:
def __init__(self, name="", dscore=0, mscore=0, durl="", murl=""): 
    self.name = name
    self.dscore = float(dscore)
    self.mscore = float(mscore)
    self.durl = durl
    self.murl = murl
def __str__(self):
    return unicode(self.name) + u' / ' + unicode(self.dscore) + u' / ' + unicode(self.mscore) \
        + u' / ' + unicode(self.durl) + u' / ' + unicode(self.murl)

The statement causing the problem is:

DataDict['MovieInfo'] = MovieInfo

and

pickle.dump(DataDict, f, True)

following is the function:

def SaveData():
global LinkUrlQueue
global MovieSet
global MovieInfo
global LinkUrlSet
global MovieUrlQueue
DataDict = {}
DataDict['LinkUrlSet'] = LinkUrlSet
DataDict['MovieSet'] = MovieSet
#DataDict['MovieInfo'] = MovieInfo
DataDict['LinkUrlQueue'] = LinkUrlQueue
DataDict['MovieUrlQueue'] = MovieUrlQueue
f = open('MovieInfo.txt', 'wb')

for item in MovieInfo:
    f.write(item.__str__().encode('utf8') + '\n'.encode('utf8'))
f.close()
try:
    print 'saving data...'
    f = open('spider.dat', 'wb')
    pickle.dump(DataDict, f, True)
    f.close()
except IOError as e:
    print 'IOError, error no: %d' % e.no
    print 'saved to spider2.dat'
    pickle.dump(DataDict, open('spider2.dat', 'wb'))
    time.sleep(10)

my complete source code:

spider.py: http://paste.ubuntu.com/7149731/

fetch.py: http://paste.ubuntu.com/7149732/

You can just download and run.

Besides, welcome any coding style suggestions

Well... I finally solve the problem by myself...

The reason for this problem is that pickle cannot handle BEAUTIFULSOUP!!! Generally, it cannot handle html parser.

I realize that when passing arguments into my functions, I should convert them into str() or unicode() then do assignments, instead of remaining them as beautifulsoup objects...

thanks for everyone~