* factory classes like:
 *
 * <pre>
 * interface Book {...}
 * public class Books {
 *   public static Book hardcover(String title) {...}
 *   public static Book paperback(String title) {...}
 * }
 * </pre>
 *
 * <p>And all the created {@code Book} instances can be tested with:
 *
 * <pre>
 * new ClassSanityTester()
 *     .forAllPublicStaticMethods(Books.class)

   * graphs. Example:
   *
   * <pre>{@code
   * static final ImmutableGraph<Country> COUNTRY_ADJACENCY_GRAPH =
   *     GraphBuilder.undirected()
   *         .<Country>immutable()
   *         .putEdge(FRANCE, GERMANY)
   *         .putEdge(FRANCE, BELGIUM)
   *         .putEdge(GERMANY, BELGIUM)
   *         .addNode(ICELAND)
   *         .build();
   * }</pre>
   *

```Python hl_lines="3  5"
{
    "name": "Bar",
    "description": "The bartenders",
    "price": 62,
    "tax": 20.2
}
```

👫 🔜 🔌 📨.

#### 📊 ⏮️ 🎏 💲 🔢

🚥 📊 ✔️ 🎏 💲 🔢 🕐, 💖 🏬 ⏮️ 🆔 `baz`:

```Python hl_lines="3  5-6"
{
    "name": "Baz",
    "description": None,
    "price": 50.2,
    "tax": 10.5,
    "tags": []
}
```

                  <div class="well">
                      In order to accept this change add the following to <code>${relativePathToMainApiChanges()}</code>:
                    <pre>${prettyPrintJson(acceptanceJson)}</pre>
                  </div>
                </div>
                </p>
                <p>

	}

	publicKey := func(priv interface{}) interface{} {
		switch k := priv.(type) {
		case *rsa.PrivateKey:
			return &k.PublicKey
		case *ecdsa.PrivateKey:
			return &k.PublicKey
		default:
			return nil
		}
	}

	pemBlockForKey := func(priv interface{}) *pem.Block {
		switch k := priv.(type) {
		case *rsa.PrivateKey:

```JSON
{
    "name": "Foo",
    "description": "An optional description",
    "price": 45.2,
    "tax": 3.5
}
```

...поскольку `description` и `tax` являются необязательными (с `None` в качестве значения по умолчанию), вот такой JSON "объект" также подходит:

```JSON
{
    "name": "Foo",
    "price": 45.2
}
```

## Объявление как параметра функции

///

## Importe `File`

Importe `File` e `UploadFile` de `fastapi`:

{* ../../docs_src/request_files/tutorial001_an_py39.py hl[3] *}

## Definir Parâmetros `File`

Crie parâmetros de arquivo da mesma forma que você faria para `Body` ou `Form`:

{* ../../docs_src/request_files/tutorial001_an_py39.py hl[9] *}

/// info | Informação

`File` é uma classe que herda diretamente de `Form`.

   *
   * <p>For example,
   *
   * <pre>{@code
   * List<String> badGuys =
   *     Arrays.asList("Inky", "Blinky", "Pinky", "Pinky", "Clyde");
   * Function<String, Integer> stringLengthFunction = ...;
   * Multimap<Integer, String> index =
   *     Multimaps.index(badGuys, stringLengthFunction);
   * System.out.println(index);
   * }</pre>
   *
   * <p>prints
   *
   * <pre>{@code

     * The pool will routinely try to pre-emptively open connections to satisfy this minimum.
     * Connections will still be closed if they idle beyond the keep-alive but will be replaced.
     */
    @JvmField val minimumConcurrentCalls: Int = 0,
    /** How long to wait to retry pre-emptive connection attempts that fail. */
    @JvmField val backoffDelayMillis: Long = 60 * 1000,

 * whenever there is a chance the check may fail "in real life". Example:
 *
 * <pre>{@code
 * Bill bill = remoteService.getLastUnpaidBill();
 *
 * // In case bug 12345 happens again we'd rather just die
 * Verify.verify(bill.status() == Status.UNPAID,
 *     "Unexpected bill status: %s", bill.status());
 * }</pre>
 *
 * <h3>Comparison to alternatives</h3>
 *