@jscanvic has added a partial ruff CI rule in #501 that checks deprecated types.

It would be nice to have more ruff linting to check for other problems, bugs and inefficiencies. The rules should be set to:

• Be in accordance with current deepinv coding conventions
• Switch off formatter so we can keep existing black formatter
• Not apply any changes, just throw warnings
• Be mostly aimed at preventing bugs & measurable inefficiencies (instead of more vague criteria like code cleanness)

Note this should also be orthogonal to type checking in #536