try {
            var f = target.getClass().getDeclaredField(name);
            f.setAccessible(true);
            return f.get(target);
        } catch (Exception e) {
            fail("access field " + name, e);
            return null;
        }
    }

    private static int invokeProtectedInt(Object target, String name, Object... params) {
        try {
            var cls = target.getClass();

{* ../../docs_src/dataclasses_/tutorial003_py310.py hl[1,4,7:10,13:16,22:24,27] *}

1. Wir importieren `field` weiterhin von Standard-`dataclasses`.

2. `pydantic.dataclasses` ist ein direkter Ersatz für `dataclasses`.

3. Die Datenklasse `Author` enthält eine Liste von `Item`-Datenklassen.

In that case, you can simply swap the standard `dataclasses` with `pydantic.dataclasses`, which is a drop-in replacement:

{* ../../docs_src/dataclasses_/tutorial003_py310.py hl[1,4,7:10,13:16,22:24,27] *}

1. We still import `field` from standard `dataclasses`.

2. `pydantic.dataclasses` is a drop-in replacement for `dataclasses`.

3. The `Author` dataclass includes a list of `Item` dataclasses.

```JSON
{
  "detail": [
    {
      "type": "missing",
      "loc": [
        "query",
        "needy"
      ],
      "msg": "Field required",
      "input": null
    }
  ]
}
```

Оскільки `needy` є обов’язковим параметром, вам потрібно вказати його в URL:

```
http://127.0.0.1:8000/items/foo-item?needy=sooooneedy
```

In OkHttp some fields of the address come from the URL (scheme, hostname, port) and the rest come from the [OkHttpClient](https://square.github.io/okhttp/5.x/okhttp/okhttp3/-ok-http-client/).

    public static final int STATUS_NOT_SUPPORTED = 0x00000001;
    /** Status indicating insufficient resources for SMB Direct */
    public static final int STATUS_INSUFFICIENT_RESOURCES = 0x00000002;

    // Message fields
    private int minVersion;
    private int maxVersion;
    private int negotiatedVersion;
    private int reserved = 0;
    private int creditsGranted;
    private int creditsRequested;

  @WeakOuter
  private final class ServiceDelegate extends AbstractService {

    // A handle to the running task so that we can stop it when a shutdown has been requested.
    // These two fields are volatile because their values will be accessed from multiple threads.
    private volatile @Nullable Cancellable runningTask;
    private volatile @Nullable ScheduledExecutorService executorService;

        }
        // Convert milliseconds to 100-nanosecond intervals
        // 1 ms = 10,000 * 100ns intervals
        long intervals = timeoutMs * 10000L;
        // MS-SMB2 timeout field is 4 bytes (uint32), so clamp to max value
        return Math.min(intervals, 0xFFFFFFFFL);
    }

    /**
     * Get the flags
     * @return the flags
     */
    public int getFlags() {

Bu durumda **FastAPI**, fonksiyonda birden fazla body parametresi olduğunu fark eder (iki parametre de Pydantic modelidir).

Bunun üzerine, body içinde anahtar (field name) olarak parametre adlarını kullanır ve şu şekilde bir body bekler:

```JSON
{
    "item": {
        "name": "Foo",
        "description": "The pretender",
        "price": 42.0,
        "tax": 3.2
    },

        assertTrue(exception instanceof Throwable);
    }

    @Test
    public void test_serialVersionUID() {
        // Test that the exception has a serialVersionUID field
        FessUserNotFoundException exception1 = new FessUserNotFoundException("user1");
        FessUserNotFoundException exception2 = new FessUserNotFoundException("user2");