code: @Nonnull
      public static <K, V> Map<K, V> putAllAndMakeImmutable(@Nonnull Map<K, V> original, @Nullable Object... a) {
          return asImmutableMap(CollectionUtils.putAll(original, a));
      }
docs: Returns a the given map enriched
  with the mappings <code>a[0] => a[1], a[2] => a[3], ...</code>.
  @param a the elements to construct a {@link Map} from.
  @return a immutable {@link Map} constructed of the specified elements.