* ParametricNullness parametric nullness}. Sometimes, code may receive a null {@code T} but store
   * a "null sentinel" to take its place. When the time comes to convert it back to a {@code T} to
   * return to a caller, the code needs to a way to return {@code null} from a method that returns
   * "plain {@code T}." This API provides that.
   */

FastAPI знает об этом и создаст документацию OpenAPI, в которой будет указано, что тело ответа отсутствует.

///

## Об HTTP статус-кодах { #about-http-status-codes }

/// note | Примечание

Если вы уже знаете, что представляют собой HTTP статус-коды, можете перейти к следующему разделу.

///

В протоколе HTTP числовой код состояния из 3 цифр отправляется как часть ответа.

		return false
	}
	prog.Scond = bits
	return true
}

// parseARM64Suffix parses the suffix attached to an ARM64 instruction.
// The input is a single string consisting of period-separated condition
// codes, such as ".P.W". An initial period is ignored.
func parseARM64Suffix(cond string) (uint8, bool) {
	if cond == "" {
		return 0, true
	}
	return parseARMCondition(cond, arm64LS, nil)
}

      // Server sent a 100-continue even though we did not request one. Try again to read the
      // actual response status.
      code == 100 -> true

      // Handle Processing (102) & Early Hints (103) and any new codes without failing
      // 100 and 101 are the exceptions with different meanings
      // But Early Hints not currently exposed
      code in (102 until 200) -> true

      else -> false
    }

3. La dataclass `Author` inclut une liste de dataclasses `Item`.

4. La dataclass `Author` est utilisée comme paramètre `response_model`.

5. Vous pouvez utiliser d'autres annotations de type standard avec des dataclasses comme corps de la requête.

    Dans ce cas, il s'agit d'une liste de dataclasses `Item`.

6. Ici, nous renvoyons un dictionnaire qui contient `items`, qui est une liste de dataclasses.

<img src="/img/tutorial/response-status-code/image01.png">

/// note | 注意

有些回應碼（見下一節）表示回應不包含本文（body）。

FastAPI 知道這點，並會產生聲明「無回應本文」的 OpenAPI 文件。

///

## 關於 HTTP 狀態碼 { #about-http-status-codes }

/// note | 注意

如果你已經知道什麼是 HTTP 狀態碼，可以直接跳到下一節。

///

在 HTTP 中，你會在回應的一部分傳回 3 位數的狀態碼。

這些狀態碼有對應的名稱以便辨識，但重點是數字本身。

簡而言之：

* `100 - 199` 表示「資訊」。你很少會直接使用它們。這些狀態碼的回應不可包含本文。

## Dependencies

FastAPI depends on Pydantic and Starlette.

### `standard` Dependencies

When you install FastAPI with `pip install "fastapi[standard]"` it comes with the `standard` group of optional dependencies:

Used by Pydantic:

* [`email-validator`](https://github.com/JoshData/python-email-validator) - for email validation.

Used by Starlette:

 * were inserted, not how those bytes were chunked into discrete put() operations. For example, the
 * following three expressions all generate colliding hash codes:
 *
 * {@snippet :
 * newHasher().putByte(b1).putByte(b2).putByte(b3).hash()
 * newHasher().putByte(b1).putBytes(new byte[] { b2, b3 }).hash()
 * newHasher().putBytes(new byte[] { b1, b2, b3 }).hash()
 * }
 *

    /**
     * Returns the type of this SID indicating the state or type of account.
     * <p>
     * SID types are described in the following table.
     * <table>
     * <caption>Type codes</caption>
     * <tr>
     * <th>Type</th>
     * <th>Name</th>
     * </tr>
     * <tr>
     * <td>SID_TYPE_USE_NONE</td>
     * <td>0</td>
     * </tr>
     * <tr>
     * <td>SID_TYPE_USER</td>

        SamrPolicyHandle handle = new SamrPolicyHandle(mockHandle, server, access);

        SmbException thrown = assertThrows(SmbException.class, handle::close);

        // SmbException constructor maps non-NT status codes to NT_STATUS_UNSUCCESSFUL
        assertEquals(0xC0000001, thrown.getNtStatus()); // NT_STATUS_UNSUCCESSFUL
        verify(mockHandle, times(1)).sendrecv(any(MsrpcSamrCloseHandle.class));
    }