ModuleNotFoundError: No module named ‘flask_cors‘解决办法。

sudo pip install -U flask-cors。

原报错：

ubuntu@VM-20-15-ubuntu:/home/project/al$ sudo python3 run.py
Traceback (most recent call last):
  File "run.py", line 4, in
    from app import al
  File "/home/project/al/app/__init__.py", line 5, in
    from flask_cors import CORS
ModuleNotFoundError: No module named 'flask_cors'

方案：sudo pip install -U flask-cors。