public <Z> IterableChecker<List<Z>, Z> toList(Function<? super T, ? extends Z> fn) {
    return check(result.stream().map(fn).collect(Collectors.toList()));
  }
Generic checker for a {@link org.immutables.criteria.Criterion}
@param <T>
criteria/common/test/org/immutables/criteria/personmodel/CriteriaChecker.java