import com.google.common.base.Function;
import java.util.concurrent.Executor;
import org.jspecify.annotations.Nullable;

/**
 * Hidden superclass of {@link FluentFuture} that provides us a place to declare special GWT
 * versions of the {@link FluentFuture#catching(Class, com.google.common.base.Function)
 * FluentFuture.catching} family of methods. Those versions have slightly different signatures.
 */

import com.google.common.base.Function;
import java.util.concurrent.Executor;
import org.jspecify.annotations.Nullable;

/**
 * Hidden superclass of {@link Futures} that provides us a place to declare special GWT versions of
 * the {@link Futures#catching(ListenableFuture, Class, com.google.common.base.Function)
 * Futures.catching} family of methods. Those versions have slightly different signatures.
 */

Esto hará que `tags` sea una lista, aunque no declare el tipo de los elementos de la lista.

## Campos de lista con parámetro de tipo { #list-fields-with-type-parameter }

Pero Python tiene una forma específica de declarar listas con tipos internos, o "parámetros de tipo":

### Declarar una `list` con un parámetro de tipo { #declare-a-list-with-a-type-parameter }

 */
@GwtCompatible
abstract class CommonPattern {
  public abstract CommonMatcher matcher(CharSequence t);

  public abstract String pattern();

  public abstract int flags();

  // Re-declare this as abstract to force subclasses to override.
  @Override
  public abstract String toString();

  public static CommonPattern compile(String pattern) {
    return Platform.compilePattern(pattern);
  }

package com.google.common.util.concurrent;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.J2ktIncompatible;

/**
 * Hidden superclass of {@link Futures} that provides us a place to declare special GWT versions of
 * the {@link Futures#catching(ListenableFuture, Class, com.google.common.base.Function,
 * java.util.concurrent.Executor) Futures.catching} family of methods. Those versions have slightly

{* ../../docs_src/bigger_applications/app_an_py39/routers/users.py hl[1,3] title["app/routers/users.py"] *}

### *Path operations* with `APIRouter` { #path-operations-with-apirouter }

And then you use it to declare your *path operations*.

Use it the same way you would use the `FastAPI` class:

{* ../../docs_src/bigger_applications/app_an_py39/routers/users.py hl[6,11,16] title["app/routers/users.py"] *}

To make clear that you license your contribution under
the [Apache License Version 2.0, January 2004](http://www.apache.org/licenses/LICENSE-2.0)
you have to acknowledge this by using the following check-box.

- [ ] I hereby declare this contribution to be licenced under the [Apache License Version 2.0, January 2004](http://www.apache.org/licenses/LICENSE-2.0)

  # To guarantee Maintained check is occasionally updated. See
  # https://github.com/ossf/scorecard/blob/main/docs/checks.md#maintained
  schedule:
    - cron: '26 3 * * 2'
  push:
    branches: [ "master" ]

# Declare default permissions as read only.
permissions: read-all

jobs:
  analysis:
    if: github.repository == 'tensorflow/tensorflow' # Don't do this in forks
    name: Scorecards analysis
    runs-on: ubuntu-latest

Essas funções podem ser declaradas com `async def` ou `def` normal.

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

Para adicionar uma função que deve rodar antes de a aplicação iniciar, declare-a com o evento `"startup"`:

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

Nesse caso, a função de manipulador do evento `startup` inicializará os itens do "banco de dados" (apenas um `dict`) com alguns valores.

Обратите внимание, что функция `Field` импортируется непосредственно из `pydantic`, а не из `fastapi`, как все остальные функции (`Query`, `Path`, `Body` и т.д.).

///

## Объявление атрибутов модели { #declare-model-attributes }

Вы можете использовать функцию `Field` с атрибутами модели:

{* ../../docs_src/body_fields/tutorial001_an_py310.py hl[11:14] *}