... importing a billing client themselves. A check looking only at direct imports would clear all three on day one and flag nothing. What you want is transitive reach, is there any path from this route to the payment module, which is a slightly bigger script and the same idea. The bigger one is that the check must not compare against a list you maintain. If it does, day one flags five files, somebody adds five entries to an ignore file ... ... being awkward. Predicate and redact aim at different parties, so in the middle the subtraction stops being free and picks up a floor set by the reader instead of the sender. We ended up with two strengths in one module