I write a project with tornado,but this is always a exception in my log file : This is the error log:

[I 160308 11:09:59 web:1908] 200 GET /admin/realtime (117.93.180.216) 107.13ms
[E 160308 11:09:59 http1connection:54] Uncaught exception
    Traceback (most recent call last):
      File "/usr/local/lib/python3.4/dist-packages/tornado/http1connection.py", line 238, in _read_message
        delegate.finish()
      File "/usr/local/lib/python3.4/dist-packages/tornado/httpserver.py", line 290, in finish
        self.delegate.finish()
      File "/usr/local/lib/python3.4/dist-packages/tornado/web.py", line 1984, in finish
        self.execute()
      File "/usr/local/lib/python3.4/dist-packages/blueware-1.0.10/blueware/hooks/framework_tornado/web.py", line 480, in _bw_wrapper__RequestDispatcher_execute
        future = wrapped(*args, **kwargs)
      File "/usr/local/lib/python3.4/dist-packages/tornado/web.py", line 2004, in execute
        **self.handler_kwargs)
      File "/usr/local/lib/python3.4/dist-packages/blueware-1.0.10/blueware/hooks/framework_tornado/web.py", line 448, in _bw_wrapper_RequestHandler___init___
        return wrapped(*args, **kwargs)
      File "/usr/local/lib/python3.4/dist-packages/tornado/web.py", line 185, in __init__
        self.initialize(**kwargs)
      File "/usr/local/lib/python3.4/dist-packages/tornado/web.py", line 2714, in wrapper
        self.redirect(url)
      File "/usr/local/lib/python3.4/dist-packages/tornado/web.py", line 671, in redirect
        self.finish()
      File "/usr/local/lib/python3.4/dist-packages/blueware-1.0.10/blueware/hooks/framework_tornado/web.py", line 309, in _bw_wrapper_RequestHandler_finish_
        return wrapped(*args, **kwargs)
      File "/usr/local/lib/python3.4/dist-packages/tornado/web.py", line 934, in finish
        self.flush(include_footers=True)
      File "/usr/local/lib/python3.4/dist-packages/tornado/web.py", line 870, in flush 
        for transform in self._transforms:
    TypeError: 'NoneType' object is not iterable
[I 160308 11:10:00 web:1908] 200 GET /admin/order?order_type=1&order_status=1&page=0&action=allreal (49.89.27.173) 134.53ms


who can tell me how to sovle solve this problem ， thank you very much~~




