No module named flask guide package fails, Python3 Flask module reinstalled

In the course of the deployment environment, by pip install -r requirements.txt installation package, the result always being given the time to start the project, showed no flask module by pip install flask or not, then download the source flask, once again installed has been resolved, the following steps :

1, GIT clone

git clone https://github.com/pallets/flask

2, mounted reliance library

cd flask
python setup.py install

3, into the project can start!

Reproduced in: https: //www.cnblogs.com/li-li/p/11274643.html

In the course of the deployment environment, by pip install -r requirements.txt installation package, the result always being given the time to start the project, showed no flask module by pip install flask or not, then download the source flask, once again installed has been resolved, the following steps :

1, GIT clone

git clone https://github.com/pallets/flask

2, mounted reliance library

cd flask
python setup.py install

3, into the project can start!