Al igual que al declarar parámetros de query, cuando un atributo del modelo tiene un valor por defecto, no es obligatorio. De lo contrario, es obligatorio. Usa `None` para hacerlo solo opcional.

Por ejemplo, el modelo anterior declara un “`object`” JSON (o `dict` en Python) como:

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

 * supplementary code points, use ICU4J UCharacter and UnicodeSet (freeze() after building). For
 * basic text processing based on UnicodeSet use the ICU4J UnicodeSetSpanner.
 *
 * <p>Example usages:
 *
 * <pre>
 *   String trimmed = {@link #whitespace() whitespace()}.{@link #trimFrom trimFrom}(userInput);
 *   if ({@link #ascii() ascii()}.{@link #matchesAllOf matchesAllOf}(s)) { ... }</pre>
 *

* `Decimal`：
    * 標準的 Python `Decimal`。
    * 在請求與回應中，與 `float` 的處理方式相同。
* 你可以在此查閱所有可用的 Pydantic 資料型別：[Pydantic 資料型別](https://docs.pydantic.dev/latest/usage/types/types/)。

## 範例 { #example }

以下是一個帶有參數、使用上述部分型別的 *路徑操作 (path operation)* 範例。

{* ../../docs_src/extra_data_types/tutorial001_an_py310.py hl[1,3,12:16] *}

請注意，函式內的參數會是它們的自然資料型別，因此你可以進行一般的日期運算，例如：

* `Decimal`:
    * 标准的 Python `Decimal`。
    * 在请求和响应中被当做 `float` 一样处理。
* 您可以在这里检查所有有效的 Pydantic 数据类型: [Pydantic data types](https://docs.pydantic.dev/latest/usage/types/types/)。

## 例子 { #example }

下面是一个*路径操作*的示例，其中的参数使用了上面的一些类型。

{* ../../docs_src/extra_data_types/tutorial001_an_py310.py hl[1,3,12:16] *}

注意，函数内的参数有原生的数据类型，你可以，例如，执行正常的日期操作，如:

 * <strong>Performance</strong>).
 *
 * <p><strong>Cycle Detection</strong>
 *
 * <p>Deadlocks can arise when locks are acquired in an order that forms a cycle. In a simple
 * example involving two locks and two threads, deadlock occurs when one thread acquires Lock A, and
 * then Lock B, while another thread acquires Lock B, and then Lock A:
 *
 * <pre>
 * Thread1: acquire(LockA) --X acquire(LockB)

import okhttp3.OkHttpClient
import okhttp3.Request
import okhttp3.coroutines.executeAsync
import okhttp3.survey.types.SuiteId
import okio.ByteString.Companion.decodeHex
import okio.IOException

/** Example: "0x00,0x08",TLS_RSA_EXPORT_WITH_DES40_CBC_SHA,Y,N,[RFC4346] */
val IANA_CSV_PATTERN = "\"0x(\\w\\w),0x(\\w\\w)\",(\\w+).*".toRegex()

fun parseIanaCsvRow(s: String): SuiteId? {

  /**
   * Performs a <b>single</b> tear-down operation. See test-libraries-for-java's {@code
   * com.google.common.testing.junit3.TearDownTestCase} and {@code
   * com.google.common.testing.junit4.TearDownTestCase} for example.
   *
   * <p>A failing {@link TearDown} may or may not fail a tl4j test, depending on the version of
   * JUnit test case you are running under. To avoid failing in the face of an exception regardless

 * This annotation can be used in conjunction with {@link Inject} to specify
 * which implementation should be injected when multiple candidates exist.
 * The value represents a unique identifier for the dependency.
 * <p>
 * Example usage:
 * <pre>
 * {@literal @}Inject
 * {@literal @}Named("mysql")
 * private Repository mysqlRepository;
 * </pre>
 *
 * @see Inject
 * @see Qualifier
 * @since 4.0.0
 */
@Qualifier

 * through the Java ServiceLoader mechanism and their provided languages will be available
 * throughout the Maven build process.
 * <p>
 * Example usage:
 * <pre>
 * public class CustomLanguageProvider implements LanguageProvider {
 *     public Collection&lt;Language&gt; provides() {
 *         return Collections.singleton(language("kotlin"));
 *     }
 * }

Bir client, **query parameter**’larda **ek (extra)** veri göndermeye çalışırsa, **error** response alır.

Örneğin client, değeri `plumbus` olan bir `tool` query parameter’ı göndermeye çalışırsa:

```http
https://example.com/items/?limit=10&tool=plumbus
```

`tool` query parameter’ına izin verilmediğini söyleyen bir **error** response alır:

```json
{
    "detail": [
        {
            "type": "extra_forbidden",