docs: public static Specification<JpaTarget> isNotInRolloutGroups(final Collection<Long> groups) {
          return (targetRoot, query, cb) -> {
              final ListJoin<JpaTarget, RolloutTargetGroup> rolloutTargetJoin = targetRoot
                      .join(JpaTarget_.rolloutTargetGroup, JoinType.LEFT);
              final Predicate inRolloutGroups = rolloutTargetJoin.get(RolloutTargetGroup_.rolloutGroup)
                      .get(JpaRolloutGroup_.id).in(groups);
              rolloutTargetJoin.on(inRolloutGroups);
              return cb.isNull(rolloutTargetJoin.get(RolloutTargetGroup_.target));
          };
      }