@Override
    public CompletableFuture<Boolean> clearParents(ImmutableContextSet contexts) {
        Set<LPSubjectReference> set = this.parents.get(contexts);
        if (set == null) {
            return CompletableFuture.completedFuture(false);
        }

        this.parents.remove(contexts);
        this.service.invalidateAllCaches();
        return CompletableFuture.completedFuture(!set.isEmpty());
    }
In-memory implementation of {@link LPSubjectData}.
sponge/src/main/java/me/lucko/luckperms/sponge/service/model/calculated/CalculatedSubjectData.java