I can see this being useful for other users, so we'd definitely welcome the contribution. There are complications though. E.g., if we go the

!!

route, does that mean "don't bring in this dep through this target"? Or "don't bring in this dep through any target'? Maybe the

!!

has to be on

python_binary

or other root targets, and it means "strip this dep from the transitive closure when computed on (but not through) this target"?