There is a similar problem (Why does pip fail with bad md5 hash for package?) from 2013 the solution that I tried that worked for me is this:
sudo pip install --no-cache-dir flask
given by attolee
There is a similar problem (Why does pip fail with bad md5 hash for package?) from 2013 the solution that I tried that worked for me is this:
sudo pip install --no-cache-dir flask
given by attolee