```Python hl_lines="1"
async def needy_dependency(fresh_value: Annotated[str, Depends(get_value, use_cache=False)]):
    return {"fresh_value": fresh_value}
```

////

//// tab | Python 3.9+ nicht annotiert

/// tip | Tipp

Bevorzugen Sie die `Annotated`-Version, falls möglich.

///

```Python hl_lines="1"
async def needy_dependency(fresh_value: str = Depends(get_value, use_cache=False)):
    return {"fresh_value": fresh_value}

    }
}
```

/// tip | Consejo

Observa el server auto-generado con un valor `url` de `/api/v1`, tomado del `root_path`.

///

En la UI de los docs en <a href="http://127.0.0.1:9999/api/v1/docs" class="external-link" target="_blank">http://127.0.0.1:9999/api/v1/docs</a> se vería como:

<img src="/img/tutorial/behind-a-proxy/image03.png">

/// tip | Consejo

/// tip | Consejo

# Environment Variables { #environment-variables }

/// tip

If you already know what "environment variables" are and how to use them, feel free to skip this.

///

An environment variable (also known as "**env var**") is a variable that lives **outside** of the Python code, in the **operating system**, and could be read by your Python code (or by other programs as well).

But now, having `Query(max_length=50)` inside of `Annotated`, we are telling FastAPI that we want it to have **additional validation** for this value, we want it to have maximum 50 characters. 😎

/// tip

Here we are using `Query()` because this is a **query parameter**. Later we will see others like `Path()`, `Body()`, `Header()`, and `Cookie()`, that also accept the same arguments as `Query()`.

///

Existem algumas funcionalidades adicionais para lidar com segurança além das cobertas em [Tutorial - Guia de Usuário: Segurança](../../tutorial/security/index.md){.internal-link target=_blank}.

/// tip | Dica

As próximas seções **não são necessariamente "avançadas"**.

E é possível que para o seu caso de uso, a solução está em uma delas.

///

## Leia o Tutorial primeiro { #read-the-tutorial-first }

```

</div>

It will serve the documentation on `http://127.0.0.1:8008`.

That way, you can edit the documentation/source files and see the changes live.

/// tip

Alternatively, you can perform the same steps that scripts does manually.

Go into the language directory, for the main docs in English it's at `docs/en/`:

```console
$ cd docs/en/
```

Sie sollten dies tun, nachdem Sie alle Ihre *Pfadoperationen* hinzugefügt haben.

{* ../../docs_src/path_operation_advanced_configuration/tutorial002_py39.py hl[2, 12:21, 24] *}

/// tip | Tipp

Wenn Sie `app.openapi()` manuell aufrufen, sollten Sie vorher die `operationId`s aktualisiert haben.

///

/// warning | Achtung

Vous devriez le faire après avoir ajouté toutes vos *paramètres de chemin*.

{* ../../docs_src/path_operation_advanced_configuration/tutorial002.py hl[2,12:21,24] *}

/// tip | Astuce

Si vous appelez manuellement `app.openapi()`, vous devez mettre à jour les `operationId` avant.

///

/// warning | Attention

addAttachmentClass(attachment) {\n    $(this.getTipElement()).addClass(`${CLASS_PREFIX}-${attachment}`)\n  }\n\n  getTipElement() {\n    this.tip = this.tip || $(this.config.template)[0]\n    return this.tip\n  }\n\n  setContent() {\n    const tip = this.getTipElement()\n    this.setElementContent($(tip.querySelectorAll(SELECTOR_TOOLTIP_INNER)), this.getTitle())\n    $(tip).removeClass(`${CLASS_NAME_FADE} ${CLASS_NAME_SHOW}`)\n  }\n\n  setElementContent($element, content) {\n    if (typeof content === 'object'...