500 submitting new post

Looks like html5lib changed incompatibly in the newer version we just upgraded to:

Traceback:
File "/home/dpoirier/VE/pycon/local/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
  115.                         response = callback(request, *callback_args, **callback_kwargs)
File "/home/dpoirier/VE/pycon/local/lib/python2.7/site-packages/django/contrib/admin/options.py" in wrapper
  372.                 return self.admin_site.admin_view(view)(*args, **kwargs)
File "/home/dpoirier/VE/pycon/local/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view
  91.                     response = view_func(request, *args, **kwargs)
File "/home/dpoirier/VE/pycon/local/lib/python2.7/site-packages/django/views/decorators/cache.py" in _wrapped_view_func
  89.         response = view_func(request, *args, **kwargs)
File "/home/dpoirier/VE/pycon/local/lib/python2.7/site-packages/django/contrib/admin/sites.py" in inner
  202.             return view(request, *args, **kwargs)
File "/home/dpoirier/VE/pycon/local/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapper
  25.             return bound_func(*args, **kwargs)
File "/home/dpoirier/VE/pycon/local/lib/python2.7/site-packages/django/utils/decorators.py" in _wrapped_view
  91.                     response = view_func(request, *args, **kwargs)
File "/home/dpoirier/VE/pycon/local/lib/python2.7/site-packages/django/utils/decorators.py" in bound_func
  21.                 return func(self, *args2, **kwargs2)
File "/home/dpoirier/VE/pycon/local/lib/python2.7/site-packages/django/db/transaction.py" in inner
  223.                 return func(*args, **kwargs)
File "/home/dpoirier/VE/pycon/local/lib/python2.7/site-packages/django/contrib/admin/options.py" in add_view
  990.                 new_object = self.save_form(request, form, change=False)
File "/home/dpoirier/VE/pycon/local/lib/python2.7/site-packages/biblion/admin.py" in save_form
  56.         return form.save()
File "/home/dpoirier/VE/pycon/local/lib/python2.7/site-packages/biblion/forms.py" in save
  80.         post.teaser_html = render_func(self.cleaned_data["teaser"])
File "/home/dpoirier/VE/pycon/local/lib/python2.7/site-packages/django/utils/functional.py" in _curried
  13.         return _curried_func(*(args+moreargs), **dict(kwargs, **morekwargs))
File "/home/dpoirier/pycon/pycon/symposion/markdown_parser.py" in parse
  15.     for token in parser.parseFragment(text).childNodes:

Exception Type: AttributeError at /2014/admin/biblion/post/add/
Exception Value: childNodes