Pyvows 2.0.5 has broken tornado_pyvows

Pyvows's new release has broken tornado_pyvows.

    tornado_pyvows git:(master) ✗ pyvows vows/basecontext_vows.py

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     Vows Results
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        Async vows

         Error in topic:
        'NoneType' object is not callable

    Traceback (most recent call last):
          File "/Users/guilhermef/.virtualenvs/tornado_pyvows/lib/python2.7/site-packages/pyvows/runner/gevent.py", line 101, in _run_setup_and_topic
        topic = topic_func(*topic_list)
    TypeError: 'NoneType' object is not callable

        Nested tests following this error have not been run.
      ✓ OK » 0 honored • 0 broken (0.000431s)