No module named flask.ext

引入flask_cache时出现ModuleNotFoundError: No module named 'flask.ext'

环境：

• centos 7.3
• python 3.6
• flask 1.0.2
• flask-cache 0.13.1

引入flask_cache后运行时，出现以下错误

Traceback (most recent call last):
  File "manager.py", line 5, in 
    app = create_app('pro')
  File "./app/__init__.py", line 18, in create_app
    cache.init_app(app, config=cache_config)
  File "/prj/pro/x.groooo.com/.venv/lib/python3.6/site-packages/flask_cache/__init__.py", line 156, in init_app
    from .jinja2ext import CacheExtension, JINJA_CACHE_ATTR_NAME
  File "/prj/pro/x.groooo.com/.venv/lib/python3.6/site-packages/flask_cache/jinja2ext.py", line 33, in 
    from flask.ext.cache import make_template_fragment_key
ModuleNotFoundError: No module named 'flask.ext'
unable to load app 0 (mountpoint='') (callable not found or import error)

原因是新版本的flask插件已经不再使用 flask.ext.*形式

修改/site-packages/flask_cache/jinja2ext.py中
from flask.ext.cache import make_template_fragment_key
为
from flask_cache import make_template_fragment_key