AttributeError: 'NoneType' object has no attribute 'xpath'

[jayfk]

Package: django-selenium-test-runner

AttributeError: 'NoneType' object has no attribute 'xpath'
  File "celery/app/trace.py", line 367, in trace_task
    R = retval = fun(*args, **kwargs)
  File "celery_once/tasks.py", line 134, in __call__
    return super(QueueOnce, self).__call__(*args, **kwargs)
  File "celery/app/trace.py", line 622, in __protected_call__
    return self.run(*args, **kwargs)
  File "pyupio/packages/tasks.py", line 270, in sync_changelog
    d['parsed_changelog'] = changelogs.get(name=name, functions=fns)
  File "changelogs/changelogs.py", line 168, in get
    find_changelogs_fn=fns["find_changelogs"]
  File "pyupio/packages/tasks.py", line 257, in patched_get_urls
    d['urls'], d['repos'] = get_urls(session, name, data, find_changelogs_fn, **kwargs)
  File "changelogs/pypi.py", line 78, in get_urls
    candidates=new_candidates)
  File "changelogs/finder.py", line 208, in find_changelogs
    repos = set(find_repo_urls(session, name, candidates))
  File "changelogs/finder.py", line 74, in find_repo_urls
    for link in frozenset([str(l) for l in tree.xpath("//a/@href")]):