[python] Flask ImportError: No Module Named Flask

I had a similar problem with flasgger.

The reason for that was that I always use

sudo pip install flask

but for some reason that's not always the way to go. Sometimes, you have to do just

pip install flask

Another gotcha is that sometimes people type pip install Flask with the cap F

Posting this here in case somebody gets stuck. Let me know if it helped.

Useful Link: What is the difference between pip install and sudo pip install?