* <p>The {@code @Nullable} annotations on the {@code equalityGroup} parameter imply that the
   * objects, and the array itself, can be null. That is for programmer convenience, when the
   * objects come from factory methods that are themselves {@code @Nullable}. In reality neither the
   * array nor its contents can be null, but it is not useful to force the use of {@code
   * requireNonNull} or the like just to assert that.
   *

     */
    private synchronized void initLifecycleMap() {
        if (lifecycleMap == null) {
            lifecycleMap = new HashMap<>();

            if (lifecycles != null) {
                for (Lifecycle lifecycle : lifecycles) {
                    lifecycleMap.put(lifecycle.getId(), lifecycle);
                }
            } else {

     *
     * @param request The repository request from which this cache was retrieved, must not be {@code null}.
     * @param key The key to use associate the data with, must not be {@code null}.
     * @param data The data to store in the cache, may be {@code null}.
     */
    void put(RepositoryRequest request, Object key, Object data);

    /**

        try {
            return prompter.prompt(message, null, null);
        } catch (org.apache.maven.api.services.PrompterException e) {
            throw new PrompterException("Unable to prompt", e);
        }
    }

    @Override
    public String prompt(String message, String defaultReply) throws PrompterException {
        try {
            return prompter.prompt(message, null, defaultReply);

            if (parent != null) {
                // Parent is added as an edge, but must not cause a cycle - so we remove any other edges it has
                // in conflict
                addEdge(
                        projectMap,
                        vertexMap,
                        null,
                        projectVertex,
                        parent.getGroupId(),

   * Equivalent to {@link #expectMissing(Object[]) expectMissing}{@code (null)} except that the call
   * to {@code contains(null)} is permitted to throw a {@code NullPointerException}.
   *
   * @param message message to use upon assertion failure
   */
  protected void expectNullMissingWhenNullUnsupported(String message) {
    try {
      assertFalse(message, actualContents().contains(null));
    } catch (NullPointerException tolerated) {

            V1Field["Pydantic v1 Model"]
        end
        subgraph V1["Pydantic v1 Model"]
            V2Field["Pydantic v2 Model"]
        end
    end

    style V2 fill:#f9fff3
    style V1 fill:#fff6f0
    style V1Field fill:#fff6f0
    style V2Field fill:#f9fff3
```

...pero puedes tener modelos separados usando Pydantic v1 y v2 en la misma app.

```mermaid
graph TB
    subgraph "✅ Supported"
        direction TB

    assertEquals(0, multimap().keys().count(null));
  }

  @CollectionSize.Require(SEVERAL)
  @MapFeature.Require(ALLOWS_NULL_KEYS)
  public void testKeysWithNullKey() {
    resetContainer(mapEntry((K) null, v0()), mapEntry((K) null, v1()), mapEntry(k1(), v0()));
    Multiset<K> keys = multimap().keys();
    assertEquals(2, keys.count(null));
    assertEquals(1, keys.count(k1()));
    assertEquals(3, keys.size());

  public void testContains_nullNotContainedButQueriesSupported() {
    assertFalse("contains(null) should return false", collection.contains(null));
  }

  @CollectionFeature.Require(absent = ALLOWS_NULL_QUERIES)
  public void testContains_nullNotContainedAndUnsupported() {
    expectNullMissingWhenNullUnsupported("contains(null) should return false or throw");
  }

  @CollectionFeature.Require(ALLOWS_NULL_VALUES)

                        parent.getVersion());
            }

            if (versionRangeResult.getVersionConstraint() != null
                    && versionRangeResult.getVersionConstraint().getRange() != null
                    && versionRangeResult.getVersionConstraint().getRange().getUpperBound() == null) {
                // Message below is checked for in the MNG-2199 core IT.
                throw new UnresolvableModelException(