```

Quando você cria um gerenciador de contexto ou um gerenciador de contexto assíncrono como mencionado acima, o que ele faz é que, antes de entrar no bloco `with`, ele irá executar o código anterior ao `yield`, e depois de sair do bloco `with`, ele irá executar o código depois do `yield`.

No nosso exemplo de código acima, nós não usamos ele diretamente, mas nós passamos para o FastAPI para ele usá-lo.

Se você executar **múltiplos processos por contêiner** (por exemplo, com a imagem oficial do Docker), deve garantir que o número de processos iniciados não **consuma mais memória** do que o disponível.

On top of that, an async framework could run some sync code in a threadpool (using `asyncio.run_in_executor`), but belonging to the same request.

This was designed this way mainly to allow using the same objects "yielded" by dependencies inside of background tasks, because the exit code would be executed after the background tasks were finished.

* Any program, any code, **can only do things** when it is being **executed**. So, when there's a **process running**.
* The process can be **terminated** (or "killed") by you, or by the operating system. At that point, it stops running/being executed, and it can **no longer do things**.

Also, Couchbase recommends not using a single `Bucket` object in multiple "<abbr title="A sequence of code being executed by the program, while at the same time, or at intervals, there can be others being executed too.">thread</abbr>s", so, we can just get the bucket directly and pass it to our utility functions:

```Python hl_lines="49-53"
{!../../../docs_src/nosql_databases/tutorial001.py!}

* All of them will include the predefined `responses`.
* All these *path operations* will have the list of `dependencies` evaluated/executed before them.
    * If you also declare dependencies in a specific *path operation*, **they will be executed too**.

        test_db.unlink()
    # Import while creating the client to create the DB after starting the test session
    from docs_src.sql_databases.sql_app import main

    # Ensure import side effects are re-executed
    importlib.reload(main)
    with TestClient(main.app) as c:
        yield c
    if test_db.is_file():  # pragma: nocover
        test_db.unlink()
    os.chdir(cwd)

        test_db.unlink()
    # Import while creating the client to create the DB after starting the test session
    from docs_src.sql_databases.sql_app_py310 import alt_main

    # Ensure import side effects are re-executed
    importlib.reload(alt_main)

    with TestClient(alt_main.app) as c:
        yield c
    if test_db.is_file():  # pragma: nocover
        test_db.unlink()
    os.chdir(cwd)


@needs_py310

You don't even have to check if the token exists to return an error. You can be sure that if your function is executed, it will have a `str` in that token.

You can try it already in the interactive docs:

<img src="/img/tutorial/security/image03.png">

We are not verifying the validity of the token yet, but that's a start already.