How to fix pip hanging on uninstalling sqlalchjemy
If you don't want to type "y" (or you want to run it in a script), use
pip uninstall sqlalchemy --yes
Looks like pip uninstall prompts you with "Do you want to continue (Y/N)?", but that is not visible in cygwin or git bash for some reason.
Typing "y" and pressing enter makes the pip uninstall proceed.