EntryTransformer<String, String, String> concat =
        new EntryTransformer<String, String, String>() {
          @Override
          public String transformEntry(String key, String value) {
            return key + value;
          }
        };
    Map<String, String> transformed = transformEntries(map, concat);

     *     null arguments
     */
    @ParametricNullness
    V2 transformEntry(@ParametricNullness K key, @ParametricNullness V1 value);
  }

  /** Returns a view of an entry transformed by the specified transformer. */
  static <V2 extends @Nullable Object, K extends @Nullable Object, V1 extends @Nullable Object>
      Entry<K, V2> transformEntry(

     *     null arguments
     */
    @ParametricNullness
    V2 transformEntry(@ParametricNullness K key, @ParametricNullness V1 value);
  }

  /** Returns a view of an entry transformed by the specified transformer. */
  static <V2 extends @Nullable Object, K extends @Nullable Object, V1 extends @Nullable Object>
      Entry<K, V2> transformEntry(

    EntryTransformer<String, Integer, String> transformer =
        new EntryTransformer<String, Integer, String>() {
          @Override
          public String transformEntry(String key, Integer value) {
            return (value >= 0) ? key : "no" + key;
          }
        };
    Multimap<String, String> transformed = Multimaps.transformEntries(multimap, transformer);

      this.transformer = checkNotNull(transformer);
    }

    Collection<V2> transform(@ParametricNullness K key, Collection<V1> values) {
      Function<? super V1, V2> function = v1 -> transformer.transformEntry(key, v1);
      if (values instanceof List) {
        return Lists.transform((List<V1>) values, function);
      } else {
        return Collections2.transform(values, function);
      }
    }

      this.transformer = checkNotNull(transformer);
    }

    Collection<V2> transform(@ParametricNullness K key, Collection<V1> values) {
      Function<? super V1, V2> function = v1 -> transformer.transformEntry(key, v1);
      if (values instanceof List) {
        return Lists.transform((List<V1>) values, function);
      } else {
        return Collections2.transform(values, function);
      }
    }