You can have strict lint checks enforced with pre-commit hooks/ci checks. My current team I've been adding type checker tests (mypy + pyright) and for now as we're missing types I have type checkers on a nice rule of any prs you make must decrease the number of type errors (by 5, but up to you how harsh you want to be) in master to be merged forcing people to add more types. Once the type hints eventually hit 0 on our current strictness settings I'll gradually increase strictness requirements higher. Full strictness of no Any's anywhere including intermediates isn't really possible as a number of 3rd party packages lack types (tensorflow is especially sad with types). But we can get many of the strictness and that should cover a large number of basic bugs.