Attached is the patch to fix RM #3780 pgAdmin4 lacks ability to specify NULL values in CSV export.
Please review it.
A few points;
- You've included code from backports.csv, but per the licence you need to include a description of the changes made.
- Shouldn't backports.csv be removed from requirements.txt, or is it used elsewhere?
- If the previous point is true, then I'm fairly sure there is code in one or more of the many package build scripts that adds an __init__.py file to backports.csv in the venv that's created.
