*       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless
 *       of the type argument supplied by the user of the class: For example, {@code

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless
 *       of the type argument supplied by the user of the class: For example, {@code

Estas funciones pueden ser declaradas con `async def` o `def` normal.

### Evento `startup` { #startup-event }

Para añadir una función que debería ejecutarse antes de que la aplicación inicie, declárala con el evento `"startup"`:

{* ../../docs_src/events/tutorial001_py39.py hl[8] *}

En este caso, la función manejadora del evento `startup` inicializará los ítems de la "base de datos" (solo un `dict`) con algunos valores.

 */
public abstract class ConstructorUtil {

    /**
     * Do not instantiate.
     */
    protected ConstructorUtil() {
    }

    /**
     * Creates and initializes a new instance of the class declared by the specified constructor with the given initialization parameters.
     *
     * @param <T> the type of the object
     * @param constructor the constructor (must not be {@literal null})

   * Throwable}. But we <i>can</i> write {@code sneakyThrow(t);}.
   *
   * <p>We sometimes also use {@code sneakyThrow} for testing how our code responds to
   * sneaky checked exception.
   *
   * @return never; this method declares a return type of {@link Error} only so that callers can
   *     write {@code throw sneakyThrow(t);} to convince the compiler that the statement will always
   *     throw.
   */
  @CanIgnoreReturnValue

	constChase  = AIsLowerA  // forward declaration to exported ident

	// Deprecated: use B.
	A         = 1
	a         = 11
	A64 int64 = 1

	AIsLowerA = a // previously declared
)

const (
	ConversionConst = MyInt(5)
)

// Variables from function calls.
var (
	V = ptwo.F()
	// Deprecated: use WError.
	VError = BarE()
	V1     = Bar1(1, 2, 3)
	V2     = ptwo.G()
)

You can declare a parameter of type `Response` in your *path operation function* (as you can do for cookies).

And then you can set headers in that *temporal* response object.

{* ../../docs_src/response_headers/tutorial002_py39.py hl[1, 7:8] *}

And then you can return any object you need, as you normally would (a `dict`, a database model, etc).

* A documentação alternativa também irá refletir o novo parâmetro da _query_ e o corpo:

![ReDoc](https://fastapi.tiangolo.com/img/index/index-06-redoc-02.png)

### Recapitulando { #recap }

Resumindo, você declara **uma vez** os tipos dos parâmetros, corpo etc. como parâmetros de função.

Você faz isso com os tipos padrão do Python moderno.

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless
 *       of the type argument supplied by the user of the class: For example, {@code

 *       typically because the type forbids nullable type arguments: For example, {@code
 *       ImmutableList.get} returns {@code E}, but that value is never {@code null}. (Accordingly,
 *       {@code ImmutableList} is declared to forbid {@code ImmutableList<@Nullable String>}.)
 *   <li>methods whose return type is a type variable but which can return {@code null} regardless
 *       of the type argument supplied by the user of the class: For example, {@code