Traceback (most recent call last):
  File "/usr/lib/mailman/bin/withlist", line 299, in <module>
    main()
  File "/usr/lib/mailman/bin/withlist", line 277, in main
    r = do_list(listname, args, func)
  File "/usr/lib/mailman/bin/withlist", line 202, in do_list
    return func(m, *args)
  File "/usr/lib/mailman/bin/fix_url.py", line 81, in fix_url
    mlist.web_page_url = web_page_url
AttributeError: 'NoneType' object has no attribute 'web_page_url'