help(pyexpat) causes an exception:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/neal/python/dev/py3k/Lib/site.py", line 350, in __call__
    return pydoc.help(*args, **kwds)
  File "/home/neal/python/dev/py3k/Lib/pydoc.py", line 1685, in __call__
    self.help(request)
  File "/home/neal/python/dev/py3k/Lib/pydoc.py", line 1729, in help
    else: doc(request, 'Help on %s:')
  File "/home/neal/python/dev/py3k/Lib/pydoc.py", line 1512, in doc
    pager(render_doc(thing, title, forceload))
  File "/home/neal/python/dev/py3k/Lib/pydoc.py", line 1490, in 
render_doc
    return title % desc + '\n\n' + text.document(object, name)
  File "/home/neal/python/dev/py3k/Lib/pydoc.py", line 319, in document
    if inspect.ismodule(object): return self.docmodule(*args)
  File "/home/neal/python/dev/py3k/Lib/pydoc.py", line 1076, in 
docmodule
    contents.append(self.document(value, key, name))
  File "/home/neal/python/dev/py3k/Lib/pydoc.py", line 320, in document
    if inspect.isclass(object): return self.docclass(*args)
  File "/home/neal/python/dev/py3k/Lib/pydoc.py", line 1126, in docclass
    mro = deque(inspect.getmro(object))
TypeError: 'NoneType' object is not iterable