Watch out for lurking state in long running envs

This is part of the Semicolon&Sons Code Diary - consisting of lessons learned on the job. You're in the python category.

Last Updated: 2021-05-16

When first using Jupyter notebooks in the Python world, I spent a half hour debugging something only to find out that a variable contained state that was defined through (already executed) cells that were since removed from the notebook.

Therefore the first port of call when dealing with issues in such development environments should be to rerun everything from scratch and start with a blank slate.