Python Flask import Error of module that isn´t being imported

Question

I have a flask app running in Google App Engine. Yesterday, I deployed a new version of my app where I only change the HTML style. It deployed as it was supposed to. Today, I realized that I didn't change the title for each corresponding HTML page, so I only changed the title tag in each HTML page. I deployed the app again and now I'm getting this strange error of an Import Error for a module that I have never even used. How can I fix this?

The error:

ImportError: cannot import name 'json' from 'itsdangerous' (/layers/google.python.pip/pip/lib/python3.7/site-packages/itsdangerous/__init__.py)

EDIT FEB 24, 2022:

as you can see, the original folder to python3.7 has been replaced with python3.9

Is this normal in GAE?

Answer 1

This issue on Flask's GitHub is related.

Either update to Flask>2, or if that's not possible pin ItsDangerous<2 and MarkupSafe<2.

To pin to lower versions in a requirements.txt file:

flask==1.1.4
itsdangerous==1.1.0
markupsafe==1.1.1