public static boolean supports(Map<Integer, SortedSet<LayoutFeature>> map,
      final LayoutFeature f, final int lv) {
    final SortedSet<LayoutFeature> set =  map.get(lv);
    return set != null && set.contains(f);
  }
@Test
  public void testDataNodeFeature() {
    final LayoutFeature first = DataNodeLayoutVersion.Feature.FIRST_LAYOUT; 
    assertTrue(DataNodeLayoutVersion.supports(LAST_NON_RESERVED_COMMON_FEATURE,
        first.getInfo().getLayoutVersion()));
    assertEquals(LAST_COMMON_FEATURE.getInfo().getLayoutVersion() - 1,
        first.getInfo().getLayoutVersion());
  }