* Converter.apply (like Converter.convert) is capable of accepting null inputs. However, a
 * supertype of `Function<A, B>` turns out to be massively more useful to callers in practice: They
 * want their output to be non-null in operations like `stream.map(myConverter)`, and we can
 * guarantee that as long as we also require the input type to be non-null[*] (which is a
 * requirement that existing callers already fulfill).

of releasing and managing open source software. We’ve seen incredible support and enthusiasm from
thousands of people who have already contributed to our projects — and we want to ensure our community
continues to be truly open for everyone.

This code of conduct outlines our expectations for participants, as well as steps to reporting

      return network.incidentNodes(edge);
    }

    @Override
    public Set<E> adjacentEdges(E edge) {
      return network.adjacentEdges(edge);
    }

    // _don't_ override edge*Connecting*; we want the behavior from AbstractNetwork
  }

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

<details markdown="1">
<summary>または<code>async def</code>を使います...</summary>

`async` / `await`を使用するときは、 `async def`を使います:

```Python hl_lines="7 12"
from fastapi import FastAPI

app = FastAPI()


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

<img src="/img/python-types/image05.png">

Sans types, c'est presque impossible à réaliser.

Vous remarquerez que la variable `item` n'est qu'un des éléments de la list `items`.

Et pourtant, l'éditeur sait qu'elle est de type `str` et pourra donc vous aider à l'utiliser.

#### `Tuple` et `Set`

C'est le même fonctionnement pour déclarer un `tuple` ou un `set` :

{*../../docs_src/python_types/tutorial007.py hl[1,4] *}

Não faz diferença. O **FastAPI** sabe o que fazer.

/// note | Nota

Caso você não conheça, veja em [Async: *"Com Pressa?"*](../../async.md#com-pressa){.internal-link target=_blank} a sessão acerca de `async` e `await` na documentação.

///

## Integrando com OpenAPI

Todas as declarações de requisições, validações e requisitos para suas dependências (e sub-dependências) serão integradas em um mesmo esquema OpenAPI.

	default:
		sftpLogOnceIf(context.Background(), err, "unknown-error-sftp")
	}
}

func filterAlgos(arg string, want []string, allowed []string) []string {
	var filteredAlgos []string
	found := false
	for _, algo := range want {
		if len(algo) == 0 {
			continue
		}
		for _, allowedAlgo := range allowed {
			algo := strings.ToLower(strings.TrimSpace(algo))

				// otherwise it may lead to index out of range error in
				// assertion following this.
				if !testCase.versioned {
					if len(testCase.resultL.Objects) != len(resultL.Objects) {
						t.Logf("want: %v", objInfoNames(testCase.resultL.Objects))
						t.Logf("got: %v", objInfoNames(resultL.Objects))

In this case, the task function will write to a file (simulating sending an email).

And as the write operation doesn't use `async` and `await`, we define the function with normal `def`:

{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}

## Add the background task { #add-the-background-task }

Nesse caso, a função de tarefa gravará em um arquivo (simulando o envio de um e-mail).

E como a operação de gravação não usa `async` e `await`, definimos a função com `def` normal:

{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}

## Adicionar a tarefa em segundo plano