return CollectCollectors.flatteningToImmutableListMultimap(keyFunction, valuesFunction);
  }

  /**
   * Returns the empty multimap.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  // Casting is safe because the multimap will never hold any elements.
  @SuppressWarnings("unchecked")
  public static <K, V> ImmutableListMultimap<K, V> of() {

Auf diese Weise müssen Sie Ihre lokale Version nicht „installieren“, um jede Änderung testen zu können.

/// note | "Technische Details"

Das geschieht nur, wenn Sie die Installation mit der enthaltenen `requirements.txt` durchführen, anstatt `pip install fastapi` direkt auszuführen.

`Optional[Something]` là một cách viết ngắn gọn của `Union[Something, None]`, chúng là tương đương nhau.

Điều này cũng có nghĩa là trong Python 3.10, bạn có thể sử dụng `Something | None`:

//// tab | Python 3.10+

```Python hl_lines="1"
{!> ../../docs_src/python_types/tutorial009_py310.py!}
```

# 关于 HTTPS

人们很容易认为 HTTPS 仅仅是“启用”或“未启用”的东西。

但实际情况比这复杂得多。

/// note | 提示

如果你很赶时间或不在乎，请继续阅读下一部分，下一部分会提供一个step-by-step的教程，告诉你怎么使用不同技术来把一切都配置好。

///

要从用户的视角**了解 HTTPS 的基础知识**，请查看 <a href="https://howhttps.works/" class="external-link" target="_blank">https://howhttps.works/</a>。

现在，从**开发人员的视角**，在了解 HTTPS 时需要记住以下几点：

* 要使用 HTTPS，**服务器**需要拥有由**第三方**生成的**"证书(certificate)"**。
     * 这些证书实际上是从第三方**获取**的，而不是“生成”的。
* 证书有**生命周期**。

   informed of the possibility of such damages. This limitation of liability
   shall not apply to liability for death or personal injury resulting from such
   party’s negligence to the extent applicable law prohibits such limitation.
   Some jurisdictions do not allow the exclusion or limitation of incidental or
   consequential damages, so this exclusion and limitation may not apply to You.

8. Litigation

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
def read_root():
    return {"Hello": "World"}


@app.get("/items/{item_id}")
def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

### Dockerfile

Agora, no mesmo diretório do projeto, crie um arquivo `Dockerfile` com:

```{ .dockerfile .annotate }
# (1)
FROM python:3.9

[kubernetes-node-linux-arm64.tar.gz](https://dl.k8s.io/v1.10.8/kubernetes-node-linux-arm64.tar.gz) | `65c9d79ed0b460191df5956f7bac64212839a0296b40b32331e0f8d0a7a32d84`
[kubernetes-node-linux-ppc64le.tar.gz](https://dl.k8s.io/v1.10.8/kubernetes-node-linux-ppc64le.tar.gz) | `ea887de37de4681472878b9fb3d5cf7294d92660195b20c3282de54389a7becb`

Successfully built docs for: es
Copying en index.md to README.md
```

</div>

Cela génère tous les documents à `./docs_build/` pour chaque langue. Cela inclut l'ajout de tout fichier dont la traduction est manquante, avec une note disant que "ce fichier n'a pas encore de traduction". Mais vous n'avez rien à faire avec ce répertoire.

Ensuite, il construit tous ces sites MkDocs indépendants pour chaque langue, les combine, et génère le résultat final à `./site/`.

   informed of the possibility of such damages. This limitation of liability
   shall not apply to liability for death or personal injury resulting from such
   party’s negligence to the extent applicable law prohibits such limitation.
   Some jurisdictions do not allow the exclusion or limitation of incidental or
   consequential damages, so this exclusion and limitation may not apply to You.

8. Litigation

                            + validVersions + ". Building this project requires a newer version of Maven.",
                    tracker);

        } else if (olderThanAll) {
            // note this will not be hit for Maven 1.x project.xml as it is an incompatible schema
            addViolation(
                    problems,
                    Severity.FATAL,
                    Version.V20,