code: public static Set<IndexFlavor> complementOf(final Set<IndexFlavor> indexFlavors) {
          final Set<IndexFlavor> set = allOf();
          set.removeAll(indexFlavors);
          return set;
      }
docs: Returns a set containing all the known index flavours, except those is the given set
  @param indexFlavors The index flavours which will not be included in the returned set
  @return The complement of the given set of index flavours