checkNotNull(entry);
        map.put(entry.getKey(), entry.getValue());
      }
      return Maps.immutableEnumMap(map);
    }
  }

  public static class ImmutableMapCopyOfEnumMapGenerator extends TestEnumMapGenerator {
    @Override
    protected Map<AnEnum, String> create(Entry<AnEnum, String>[] entries) {
      EnumMap<AnEnum, String> map = new EnumMap<>(AnEnum.class);