code: public static <K, V> Map<K, V> transform(Map<K, V> map, Transformer<V> transformer) {
  
      Assert.notNull(map, "Map is required");
      Assert.notNull(transformer, "Transformer is required");
  
      return map.entrySet().stream().collect(Collectors.toMap(Map.Entry::<K>getKey,
        (entry) -> transformer.transform(entry.getValue())));
    }
docs: Transforms the values of the given Map with the specified Transformer.
  
  @param <K> Class type of the key.
  @param <V> Class type of the value.
  @param map {@link Map} to transform.
  @param transformer {@link Transformer} used to transform the {@link Map}'s values.
  @return a new {@link Map} from the given {@link Map} transformed by the {@link Transformer}.
  @throws IllegalArgumentException if either the {@link Map} or {@link Transformer} are null.
  @see org.cp.elements.lang.Transformer
  @see java.util.Map