werkzeug secure_filename str/bytes crash

gistfile1.txt

Traceback (most recent call last):
  File "/usr/local/lib/python3.3/site-packages/flask/app.py", line 1827, in __call__
    return self.wsgi_app(environ, start_response)
  File "/usr/local/lib/python3.3/site-packages/flask/app.py", line 1811, in wsgi_app
    response = self.make_response(self.handle_exception(e))
  File "/usr/local/lib/python3.3/site-packages/flask/app.py", line 1394, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/local/lib/python3.3/site-packages/flask/_compat.py", line 38, in reraise
    raise value
  File "/usr/local/lib/python3.3/site-packages/flask/app.py", line 1808, in wsgi_app
    response = self.full_dispatch_request()
  File "/usr/local/lib/python3.3/site-packages/flask/app.py", line 1468, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/usr/local/lib/python3.3/site-packages/flask/app.py", line 1372, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/usr/local/lib/python3.3/site-packages/flask/_compat.py", line 38, in reraise
    raise value
  File "/usr/local/lib/python3.3/site-packages/flask/app.py", line 1466, in full_dispatch_request
    rv = self.dispatch_request()
  File "/usr/local/lib/python3.3/site-packages/flask/app.py", line 1452, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/Users/anton/Sites/ostensible/ostensible.py", line 314, in upload_file
    filename = secure_filename(file.filename)
  File "/usr/local/lib/python3.3/site-packages/werkzeug/utils.py", line 279, in secure_filename
    filename = filename.replace(sep, ' ')
TypeError: expected bytes, bytearray or buffer compatible object