ImportError：无法导入名称'UserAgentMixin'

Question

我想初始化我的Flask DB时遇到问题，这是终端结果：

user@Pc:~/Documents/test$ flask db init
Traceback (most recent call last):
  File "/home/user/.local/bin/flask", line 7, in <module>
    from flask.cli import main
  File "/home/user/.local/lib/python3.6/site-packages/flask/__init__.py", line 17, in <module>
    from werkzeug.exceptions import abort
  File "/home/user/.local/lib/python3.6/site-packages/werkzeug/__init__.py", line 151, in <module>
    __import__('werkzeug.exceptions')
  File "/home/user/.local/lib/python3.6/site-packages/werkzeug/exceptions.py", line 71, in <module>
    from werkzeug.wrappers import Response
  File "/home/user/.local/lib/python3.6/site-packages/werkzeug/wrappers/__init__.py", line 30, in <module>
    from .request import PlainRequest
  File "/home/user/.local/lib/python3.6/site-packages/werkzeug/wrappers/request.py", line 6, in <module>
    from .user_agent import UserAgentMixin
  File "/home/user/.local/lib/python3.6/site-packages/werkzeug/wrappers/user_agent.py", line 1, in <module>
    from ..useragents import UserAgent
  File "/home/user/.local/lib/python3.6/site-packages/werkzeug/useragents.py", line 212, in <module>
    from werkzeug.wrappers import UserAgentMixin  # noqa
ImportError: cannot import name 'UserAgentMixin'

我正在使用Flask，SQLAlchemy，Python和PostgreSQL使用Ubuntu 18.04 LTS。从哪里发生此错误，我该如何解决？

P.S：我跟随mega tutorial关于Flask

Answer 1

尝试pip install Werkzeug

UserAgentMixin来自werkzeug！

ref：https://tedboy.github.io/flask/generated/generated/werkzeug.UserAgentMixin.html