checkState(newMap instanceof MapMakerInternalMap);
        newMap.putAll(map);
        return newMap;
      }
    };
  }

  enum SortedMapImpl implements MapsImplEnum {
    TreeMapImpl {
      @Override
      public <K extends Comparable<K>, V> SortedMap<K, V> create(Map<K, V> map) {
        SortedMap<K, V> result = Maps.newTreeMap();
        result.putAll(map);
        return result;
      }