```Python
q: Union[str, None] = Query(default=None, max_length=50)
```

Cela va valider les données, montrer une erreur claire si ces dernières ne sont pas valides, et documenter le paramètre dans le schéma `OpenAPI` de cette *path operation*.

## Rajouter plus de validation

Vous pouvez aussi rajouter un second paramètre `min_length` :

{* ../../docs_src/query_params_str_validations/tutorial003.py hl[9] *}

# Return a Response Directly { #return-a-response-directly }

When you create a **FastAPI** *path operation* you can normally return any data from it: a `dict`, a `list`, a Pydantic model, a database model, etc.

By default, **FastAPI** would automatically convert that return value to JSON using the `jsonable_encoder` explained in [JSON Compatible Encoder](../tutorial/encoder.md){.internal-link target=_blank}.

Una aplicación (instance) de `FastAPI` tiene un método `.openapi()` que se espera que devuelva el esquema de OpenAPI.

Como parte de la creación del objeto de la aplicación, se registra una *path operation* para `/openapi.json` (o para lo que sea que configures tu `openapi_url`).

Simplemente devuelve un response JSON con el resultado del método `.openapi()` de la aplicación.

}

// rebalanceAdminStatus holds rebalance status related information exported to mc, console, etc.
type rebalanceAdminStatus struct {
	ID        string                // identifies the ongoing rebalance operation by a uuid
	Pools     []rebalancePoolStatus `json:"pools"` // contains all pools, including inactive
	StoppedAt time.Time             `json:"stoppedAt"`
}

Por ejemplo, para declarar un header de `X-Token` que puede aparecer más de una vez, puedes escribir:

{* ../../docs_src/header_params/tutorial003_an_py310.py hl[9] *}

Si te comunicas con esa *path operation* enviando dos headers HTTP como:

```
X-Token: foo
X-Token: bar
```

El response sería como:

```JSON
{
    "X-Token values": [
        "bar",
        "foo"
    ]
}
```

			var deleteMarkers uint64

			for i, nerr := range errs {
				if nerr != nil {
					continue
				}
				for _, fi := range versions[i].Versions {
					if fi.Deleted {
						// Delete markers are a write operation not a permanent delete.
						deleteMarkers++
						continue
					}
					permanentDeletes++
				}
			}
			if deleteMarkers > 0 {
				p.storage.setWriteAttribute(p.totalWrites.Add(deleteMarkers))
			}

        }
    }

    @Nested
    @DisplayName("WriteBytesWireFormat Tests")
    class WriteBytesWireFormatTests {

        @Test
        @DisplayName("Should always return 0 for write operation")
        void testWriteBytesWireFormat() {
            byte[] buffer = new byte[64];
            int result = notification.writeBytesWireFormat(buffer, 0);
            assertEquals(0, result);

   * equivalent to that of calling {@code put(k, v)} on this map once for each mapping from key
   * {@code k} to value {@code v} in the specified map. The behavior of this operation is undefined
   * if the specified map is modified while the operation is in progress.
   */
  public void putAll(Map<? extends K, ? extends Long> m) {
    m.forEach(this::put);
  }

  /**

     * Creates a new CreateForm instance.
     */
    public CreateForm() {
    }

    /** The IDs of label types associated with this file configuration. */
    public String[] labelTypeIds;

    /** The CRUD operation mode for this form. */
    @ValidateTypeFailure
    public Integer crudMode;

    /** The name of the file configuration (required, maximum 200 characters). */
    @Required
    @Size(max = 200)

        assertNull(exception.getCause());
    }

    public void test_constructorWithMessageAndCause() {
        // Test constructor with message and cause
        String message = "Storage operation failed";
        Exception cause = new RuntimeException("Underlying error");
        StorageException exception = new StorageException(message, cause);

        assertNotNull(exception);