Error when updating contents which name is as Unicode.

error.txt

2015-06-16 09:42:09,565 ERROR [waitress][Dummy-4] Exception when serving /manage/terms/ティ/@@properties
Traceback (most recent call last):
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/waitress/channel.py", line 337, in service
    task.service()
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/waitress/task.py", line 173, in service
    self.execute()
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/waitress/task.py", line 392, in execute
    app_iter = self.channel.server.application(env, start_response)
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/pyramid-1.6a1-py3.4.egg/pyramid/router.py", line 223, in __call__
    response = self.invoke_subrequest(request, use_tweens=True)
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/pyramid-1.6a1-py3.4.egg/pyramid/router.py", line 198, in invoke_subrequest
    response = handle_request(request)
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/pyramid_debugtoolbar-2.4-py3.4.egg/pyramid_debugtoolbar/toolbar.py", line 178, in toolbar_tween
    return handler(request)
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/pyramid-1.6a1-py3.4.egg/pyramid/tweens.py", line 20, in excview_tween
    response = handler(request)
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/pyramid_tm-0.12-py3.4.egg/pyramid_tm/__init__.py", line 99, in tm_tween
    reraise(*exc_info)
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/pyramid_tm-0.12-py3.4.egg/pyramid_tm/compat.py", line 15, in reraise
    raise value
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/pyramid_tm-0.12-py3.4.egg/pyramid_tm/__init__.py", line 87, in tm_tween
    manager.commit()
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/transaction-1.4.4-py3.4.egg/transaction/_manager.py", line 111, in commit
    return self.get().commit()
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/transaction-1.4.4-py3.4.egg/transaction/_transaction.py", line 280, in commit
    reraise(t, v, tb)
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/transaction-1.4.4-py3.4.egg/transaction/_compat.py", line 56, in reraise
    raise value
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/transaction-1.4.4-py3.4.egg/transaction/_transaction.py", line 271, in commit
    self._commitResources()
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/transaction-1.4.4-py3.4.egg/transaction/_transaction.py", line 417, in _commitResources
    reraise(t, v, tb)
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/transaction-1.4.4-py3.4.egg/transaction/_compat.py", line 56, in reraise
    raise value
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/transaction-1.4.4-py3.4.egg/transaction/_transaction.py", line 394, in _commitResources
    rm.tpc_vote(self)
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/ZODB-4.2.0-py3.4.egg/ZODB/Connection.py", line 786, in tpc_vote
    s = vote(transaction)
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/ZODB-4.2.0-py3.4.egg/ZODB/FileStorage/FileStorage.py", line 717, in tpc_vote
    self._file.write(h.asString())
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/ZODB-4.2.0-py3.4.egg/ZODB/FileStorage/format.py", line 287, in asString
    return b"".join(map(as_bytes, [s, self.user, self.descr, self.ext]))
  File "/home/hirokiky/dev/deepthought/env/lib/python3.4/site-packages/ZODB-4.2.0-py3.4.egg/ZODB/utils.py", line 90, in as_bytes
    return str(obj).encode("ascii")
UnicodeEncodeError: 'ascii' codec can't encode characters in position 14-15: ordinal not in range(128)