Struggling with this concept please help

[George]

Hello everyone I know many have helped but I cannot get this to work
out correctly. I cannot use BeautifulSoup at all. I need to:
  Parse the HTML and extracting all the links, convert them to IP
addresses, and build a list of all these IP addresses, thwn I need to
sort the list and remove the duplicates so that unit testing will work.
Please help I have never done python before and I can't seem to get the
hang of it.

"""
Module to print IP addresses of tags in web file containing HTML

>>> showIPnums('http://22c118.cs.uiowa.edu/uploads/easy.html')
['0.0.0.0', '128.255.44.134', '128.255.45.54']


>>> showIPnums('http://22c118.cs.uiowa.edu/uploads/pytorg.html')
['0.0.0.0', '128.255.135.49', '128.255.244.57', '128.255.30.11',
'128.255.34.132', '128.255.44.51', '128.255.45.53',
'128.255.45.54', '129.255.241.42', '64.202.167.129']

"""

import htmllib
import formatter
import urllib
import socket

from urlparse import urlparse

class HTML_Parser(htmllib.HTMLParser):
    def __init__(self):
        htmllib.HTMLParser.__init__(self,
            formatter.AbstractFormatter(formatter.NullWriter()))


    def start_a(self, args):
        for key, value in args:
            if key.lower() == 'href':
                global listURL

def showIPnums(URL):
 parser = HTML_Parser()
 connect = urllib.urlopen(URL)
 data =  connect.read()
 parser.feed(data)
 parser.close()
 connect.close()

if __name__ == '__main__':
 import doctest, sys 
 doctest.testmod(sys.modules[__name__])