$ python webserver/server.py
Traceback (most recent call last):
  File "webserver/server.py", line 13, in <module>
    from ws_handler import *
  File "/home/crawl/src/webtiles/crawl/crawl-ref/source/webserver/ws_handler.py", line 2, in <module>
    import tornado.websocket
ImportError: No module named websocket