failOnErr(xl.AddVersion(fi))

	fi.VersionID = mustGetUUID()
	fi.DataDir = mustGetUUID()
	fi.Data = data2
	failOnErr(xl.AddVersion(fi))

	serialized, err := xl.AppendTo(nil)
	failOnErr(err)
	// Roundtrip data
	var xl2 xlMetaV2
	failOnErr(xl2.Load(serialized))

	// We should have one data entry
	list, err := xl2.data.list()
	failOnErr(err)
	if len(list) != 2 {
		t.Fatalf("want 1 entry, got %d", len(list))

     * Serialization stores the forward bimap, the inverse of this inverse.
     * Deserialization calls inverse() on the forward bimap and returns that
     * inverse.
     *
     * If a bimap and its inverse are serialized together, the deserialized
     * instances have inverse() methods that return the other.
     */

    @Override
    @ParametricNullness
    K checkKey(@ParametricNullness K key) {

      return mapGenerator.order(insertionOrder);
    }

    @Override
    public Map<K, V> create(Object... elements) {
      return SerializableTester.reserialize(mapGenerator.create(elements));
    }

    @Override
    public K[] createKeyArray(int length) {
      return ((TestMapGenerator<K, V>) mapGenerator.getInnerGenerator()).createKeyArray(length);
    }

            new ForwardingTestMultisetGenerator<E>(delegate) {
              @Override
              public SortedMultiset<E> create(Object... entries) {
                return SerializableTester.reserialize((SortedMultiset<E>) super.create(entries));
              }
            })
        .named(parentBuilder.getName() + " reserialized")
        .withFeatures(features)

    @Override
    public SampleElements<E> samples() {
      return gen.samples();
    }

    @Override
    public Multiset<E> create(Object... elements) {
      return (Multiset<E>) SerializableTester.reserialize(gen.create(elements));
    }

    @Override
    public E[] createArray(int length) {
      return gen.createArray(length);
    }

    @Override
    public Iterable<E> order(List<E> insertionOrder) {

```

</div>

Ensuite, allez sur l'UI `/docs`, vous verrez que **FastAPI** utilise ces **modèles** pour **documenter** l'API, et les utilisera aussi pour **sérialiser** et **valider** les données.

<div class="screenshot">
<img src="/img/tutorial/sql-databases/image01.png">
</div>

## Mettre à jour l'application avec plusieurs modèles { #update-the-app-with-multiple-models }

  public void testEqualsAndHashCode() {
    new EqualsTester()
        .addEqualityGroup(
            MANY_VALUES_PAIRED_STATS,
            DUPLICATE_MANY_VALUES_PAIRED_STATS,
            SerializableTester.reserialize(MANY_VALUES_PAIRED_STATS))
        .addEqualityGroup(
            new PairedStats(MANY_VALUES_STATS_ITERABLE, OTHER_MANY_VALUES_STATS, 1.23),
            new PairedStats(MANY_VALUES_STATS_VARARGS, OTHER_MANY_VALUES_STATS, 1.23))

  public void testEqualsAndHashCode() {
    new EqualsTester()
        .addEqualityGroup(
            MANY_VALUES_PAIRED_STATS,
            DUPLICATE_MANY_VALUES_PAIRED_STATS,
            SerializableTester.reserialize(MANY_VALUES_PAIRED_STATS))
        .addEqualityGroup(
            new PairedStats(MANY_VALUES_STATS_ITERABLE, OTHER_MANY_VALUES_STATS, 1.23),
            new PairedStats(MANY_VALUES_STATS_VARARGS, OTHER_MANY_VALUES_STATS, 1.23))

  @SuppressWarnings("RedundantOverride")
  @Override
  @J2ktIncompatible
  @GwtIncompatible
    Object writeReplace() {
    return super.writeReplace();
  }

  // This class is never actually serialized directly, but we have to make the
  // warning go away (and suppressing would suppress for all nested classes too)
  @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;

  }

  public void testNewTypeVariable_serializable() throws Exception {
    assertThrows(
        RuntimeException.class,
        () -> SerializableTester.reserialize(Types.newArtificialTypeVariable(List.class, "E")));
  }

  private static <D extends GenericDeclaration> TypeVariable<D> withBounds(
      TypeVariable<D> typeVariable, Type... bounds) {