我正在升级到jupyterhub的最新版本，但随后它要求我升级数据集（sudo jupyterhub upgrade-db）-这给出了以下错误。我在Ubuntu 16.04中运行python3.5。谢谢。
错误在下面
sudo jupyterhub upgrade-db"
[I 2019-02-08 06:01:31.146 JupyterHub dbutil:125] Upgrading sqlite:///jupyterhub.sqlite
[I 2019-02-08 06:01:31.147 JupyterHub dbutil:105] Backing up jupyterhub.sqlite => jupyterhub.sqlite.2019-02-08-060131
[I 2019-02-08 06:01:31.740 alembic.runtime.migration migration:130] Context impl SQLiteImpl.
[I 2019-02-08 06:01:31.740 alembic.runtime.migration migration:137] Will assume non-transactional DDL.
[I 2019-02-08 06:01:31.744 alembic.runtime.migration migration:356] Running upgrade 56cc5a70207e -> 99a28a4418e1, user.created and spawner.started
Traceback (most recent call last):
File "/usr/local/lib/python3.5/dist-packages/sqlalchemy/engine/base.py", line 1236, in _execute_context
cursor, statement, parameters, context
File "/usr/local/lib/python3.5/dist-packages/sqlalchemy/engine/default.py", line 536, in do_execute
cursor.execute(statement, parameters)
sqlite3.OperationalError: duplicate column name: created