t.Run(fmt.Sprintf("Test %d", i+1), func(t *testing.T) {
			var rule Rule
			err := xml.Unmarshal([]byte(tc.inputXML), &rule)
			if err != nil {
				t.Fatal(err)
			}

			if err := rule.Validate(); err != tc.expectedErr {
				t.Fatalf("%d: Expected %v but got %v", i+1, tc.expectedErr, err)
			}
		})
	}

```

</div>

Then go to the `/docs` UI, you will see that **FastAPI** is using these **models** to **document** the API, and it will use them to **serialize** and **validate** the data too.

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

## Update the App with Multiple Models { #update-the-app-with-multiple-models }

  // 2. Normalize, from bufferB to bufferA.
  val normalized = normalizeNfc(bufferB.readUtf8())
  bufferA.writeUtf8(normalized)

  // 3. For each label, convert/validate Punycode.
  val decoded = Punycode.decode(bufferA.readUtf8()) ?: return null

  // 4.1 Validate.

  // Must be NFC.
  if (decoded != normalizeNfc(decoded)) return null

  // TODO: Must not begin with a combining mark.

func ContainsReservedChars(s string) bool {
	return strings.ContainsAny(s, reservedChars)
}

// IsAccessKeyValid - validate access key for right length.
func IsAccessKeyValid(accessKey string) bool {
	return len(accessKey) >= accessKeyMinLen
}

// IsSecretKeyValid - validate secret key for right length.
func IsSecretKeyValid(secretKey string) bool {
	return len(secretKey) >= secretKeyMinLen
}

	// Immutable after creation, so no locks.
	targets map[string]*Connection

	// serverside handlers.
	handlers handlers

	// local host name.
	local string

	// authToken is a function that will validate a token.
	authToken ValidateTokenFn

	// routePath indicates the dial route path
	routePath string
}

// ManagerOptions are options for creating a new grid manager.
type ManagerOptions struct {

	if err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}
	region := globalSite.Region()
	config.SetRegion(region)
	if err = config.Validate(region, globalEventNotifier.targetList); err != nil {
		arnErr, ok := err.(*event.ErrARNNotFound)
		if ok {
			for i, queue := range config.QueueList {
				// Remove ARN not found queues, because we previously allowed

    @BeforeEach
    void setUp() {
        // 10 bytes is more than enough for the 2-byte short
        raw = new byte[10];
        buf = new NdrBuffer(raw, 0);
    }

    /**
     * Validate that the constructor masks the supplied value to its
     * lowest 8 bits (NdrShort incorrectly masks to 8 bits even though it's a short).
     */
    @ParameterizedTest
    @ValueSource(ints = { 0, 1, 255, -1, 256, 65535 })

  private transient Map<K, KeyList<K, V>> keyToKeyList;
  private transient int size;

  /*
   * Tracks modifications to keyToKeyList so that addition or removal of keys invalidates
   * preexisting iterators. This does *not* track simple additions and removals of values
   * that are not the first to be added or last to be removed for their key.
   */
  private transient int modCount;

        when(otherContext.getConfig()).thenReturn(otherConfig);
        assertFalse(response.canReuse(otherContext, false));
    }

    @Test
    @DisplayName("Should validate response correctly")
    void testIsValid() throws Exception {
        // Setup valid response
        setResponseAsReceived(response);
        setPrivateField(response, "dialectRevision", 0x0311);

Dans ce cas, comme les deux modèles sont différents, si nous annotions le type de retour de la fonction en `UserOut`, l’éditeur et les outils se plaindraient que nous renvoyons un type invalide, car ce sont des classes différentes.

C'est pourquoi, dans cet exemple, nous devons le déclarer dans le paramètre `response_model`.

... mais continuez à lire ci-dessous pour voir comment contourner cela.