* @param columnKeys column keys that may be stored in the generated table
   * @throws NullPointerException if any of the provided keys is null
   * @throws IllegalArgumentException if {@code rowKeys} or {@code columnKeys} contains duplicates
   *     or if exactly one of {@code rowKeys} or {@code columnKeys} is empty.
   */
  public static <R, C, V> ArrayTable<R, C, V> create(
      Iterable<? extends R> rowKeys, Iterable<? extends C> columnKeys) {

   *
   * @param anElement one of the elements the set should contain
   * @param otherElements the rest of the elements the set should contain
   * @return an immutable set containing those elements, minus duplicates
   */
  public static <E extends Enum<E>> ImmutableSet<E> immutableEnumSet(
      E anElement, E... otherElements) {
    return ImmutableEnumSet.asImmutable(EnumSet.of(anElement, otherElements));
  }

  /**

            fail("Should throw ChildUrlsException");
        } catch (ChildUrlsException e) {
            Set<RequestData> childUrls = e.getChildUrlList();
            // Set should handle duplicates
            assertEquals(2, childUrls.size());
        }
    }

    }
  }

  // TODO: test adding element of wrong type

  /**
   * Returns {@link Method} instances for the {@code setCount()} tests that assume multisets support
   * duplicates so that the test of {@code Multisets.forSet()} can suppress them.
   */
  @J2ktIncompatible
  @GwtIncompatible // reflection
  public static List<Method> getSetCountDuplicateInitializingMethods() {
    return asList(

                projectBuilder.build(Collections.singletonList(file), false, configuration);
        MavenProject project = result.get(0).getProject();
        // verify a few typical parameters are not duplicated
        assertEquals(1, project.getTestCompileSourceRoots().size());
        assertEquals(1, project.getCompileSourceRoots().size());
        assertEquals(1, project.getMailingLists().size());

			success: false,
		},
		// no duplicates, shall be parsed properly.
		{

        map.put(FieldNames.TIMESTAMP, timestamp.toInstant().toEpochMilli());
        return map;
    }

    /**
     * Concatenates values to a destination list, avoiding duplicates.
     * @param dest The destination list.
     * @param newValues The new values to add.
     * @param <T> The type of the values.
     */

   * collection in unspecified order.
   *
   * @param collection the elements that the set should contain
   * @return a new {@code CompactHashSet} containing those elements (minus duplicates)
   */
  public static <E extends @Nullable Object> CompactHashSet<E> create(
      Collection<? extends E> collection) {
    CompactHashSet<E> set = createWithExpectedSize(collection.size());
    set.addAll(collection);

   with its <<<DefaultModelValidator>>> implementation
   ({{{./xref/org/apache/maven/model/validation/DefaultModelValidator.html}source}})

   ** model normalization - merge duplicates: <<<ModelNormalizer>>> ({{{./apidocs/org/apache/maven/model/normalization/ModelNormalizer.html}javadoc}}),
   with its <<<DefaultModelNormalizer>>> implementation

### Preprocess the OpenAPI Specification for the Client Generator { #preprocess-the-openapi-specification-for-the-client-generator }

The generated code still has some **duplicated information**.

We already know that this method is related to the **items** because that word is in the `ItemsService` (taken from the tag), but we still have the tag name prefixed in the method name too. 😕