{* ../../docs_src/extra_models/tutorial002_py310.py hl[7,13:14,17:18,21:22] *}

## `Union` ou `anyOf` { #union-or-anyof }

Você pode declarar uma resposta como o `Union` de dois ou mais tipos, o que significa que a resposta seria qualquer um deles.

Isso será definido no OpenAPI com `anyOf`.

Para fazer isso, use a anotação de tipo padrão do Python [`typing.Union`](https://docs.python.org/3/library/typing.html#typing.Union):

{* ../../docs_src/stream_data/tutorial001_py310.py ln[32:35] hl[33] *}

Isso também significa que, com `StreamingResponse`, você tem a liberdade e a responsabilidade de produzir e codificar os bytes exatamente como precisam ser enviados, independentemente das anotações de tipo. 🤓

### Transmitir bytes { #stream-bytes }

   * only the entries for {@code keys} will be returned from {@code getAll}.
   *
   * <p>This method should be overridden when bulk retrieval is significantly more efficient than
   * many individual lookups. Note that {@link LoadingCache#getAll} will defer to individual calls
   * to {@link LoadingCache#get} if this method is not overridden.
   *

    prefers `%20` when doing its own encoding, but will retain `+` when that is
    provided.
 *  Fix: Enforce that callers call `WebSocket.close()` on IO errors. Error
    handling in WebSockets is significantly improved.
 *  Fix: Don't use SPDY/3 style header concatenation for HTTP/2 request headers.
    This could have corrupted requests where multiple headers had the same name,
    as in cookies.

 * good job of distributing the elements to the buckets to a distribution not far from uniform), and
 * amortized since some operations can trigger a hash table resize.
 *
 * <p>This implementation consumes significantly less memory than {@code java.util.LinkedHashSet} or
 * even {@code java.util.HashSet}, and places considerably less load on the garbage collector. Like

 * good job of distributing the elements to the buckets to a distribution not far from uniform), and
 * amortized since some operations can trigger a hash table resize.
 *
 * <p>This implementation consumes significantly less memory than {@code java.util.LinkedHashSet} or
 * even {@code java.util.HashSet}, and places considerably less load on the garbage collector. Like

{* ../../docs_src/body_nested_models/tutorial009_py310.py hl[7] *}

/// tip | Consejo

Ten en cuenta que JSON solo admite `str` como claves.

Pero Pydantic tiene conversión automática de datos.

Esto significa que, aunque tus clientes de API solo pueden enviar strings como claves, mientras esos strings contengan enteros puros, Pydantic los convertirá y validará.

<img src="/img/tutorial/bigger-applications/package.drawio.svg">

---

Os dois pontos `..`, como em:

```Python
from ..dependencies import get_token_header
```

significa:

* Começando no mesmo pacote em que este módulo (o arquivo `app/routers/items.py`) vive (o diretório `app/routers/`)...
* vá para o pacote pai (o diretório `app/`)...

 * from uniform), and amortized since some operations can trigger a hash table resize.
 *
 * <p>As compared with {@link java.util.LinkedHashMap}, this structure places significantly reduced
 * load on the garbage collector by only using a constant number of internal objects.
 *
 * <p>This class should not be assumed to be universally superior to {@code

La intención era evitar retener recursos por más tiempo del necesario, esperando a que la response viajara por la red.

Este cambio también significaba que si retornabas un `StreamingResponse`, el código de salida de la dependencia con `yield` ya se habría ejecutado.