constraints.Mod10Check.message              = The check digit for ${value} is invalid, Modulo 10 checksum failed.
constraints.Mod11Check.message              = The check digit for ${value} is invalid, Modulo 11 checksum failed.
constraints.ModCheck.message                = The check digit for ${value} is invalid, ${modType} checksum failed.
constraints.NotBlank.message                = {item} may not be empty.

constraints.Mod10Check.message              = The check digit for ${value} is invalid, Modulo 10 checksum failed.
constraints.Mod11Check.message              = The check digit for ${value} is invalid, Modulo 11 checksum failed.
constraints.ModCheck.message                = The check digit for ${value} is invalid, ${modType} checksum failed.
constraints.NotBlank.message                = {item} may not be empty.

   * guaranteed to be exactly +/-1 even when the data are perfectly (anti-)correlated, due to
   * numerical errors. However, it is guaranteed to be in the inclusive range [-1, +1].
   *
   * <h3>Non-finite values</h3>
   *
   * <p>If the dataset contains any non-finite values ({@link Double#POSITIVE_INFINITY}, {@link

      host = hostAndPort[0];
      portString = hostAndPort[1];
    } else {
      int colonPos = hostPortString.indexOf(':');
      if (colonPos >= 0 && hostPortString.indexOf(':', colonPos + 1) == -1) {
        // Exactly 1 colon. Split into host:port.
        host = hostPortString.substring(0, colonPos);
        portString = hostPortString.substring(colonPos + 1);
      } else {

        int lower = foundIndex;
        int upper = list.size() - 1;
        // Everything between lower and upper inclusive compares at >= 0.
        while (lower < upper) {
          int middle = (lower + upper + 1) >>> 1;
          int c = comparator.compare(list.get(middle), key);
          if (c > 0) {
            upper = middle - 1;
          } else { // c == 0
            lower = middle;
          }
        }

                  }
               },
               "gridPos": {
                  "h": 8,
                  "w": 8,
                  "x": 0,
                  "y": 0
               },
               "id": 11,
               "interval": "1m",
               "options": {
                  "legend": {
                     "calcs": [
                        "lastNotNull",
                        "max"

               }
            }
         },
         "gridPos": {
            "h": 10,
            "w": 8,
            "x": 16,
            "y": 4
         },
         "id": 11,
         "interval": "5s",
         "options": {
            "legend": {
               "calcs": [
                  "last",
                  "max"
               ],
               "displayMode": "table"

   * otherwise the default value of 11 is returned.
   */
  static int inferDistinctElements(Iterable<?> elements) {
    if (elements instanceof Multiset) {
      return ((Multiset<?>) elements).elementSet().size();
    }
    return 11; // initial capacity will be rounded up to 16
  }

  /**

   * otherwise the default value of 11 is returned.
   */
  static int inferDistinctElements(Iterable<?> elements) {
    if (elements instanceof Multiset) {
      return ((Multiset<?>) elements).elementSet().size();
    }
    return 11; // initial capacity will be rounded up to 16
  }

  /**

如在调用*路径操作函数*里的工具函数时，触发了 `HTTPException`，FastAPI 就不再继续执行*路径操作函数*中的后续代码，而是立即终止请求，并把 `HTTPException` 的 HTTP 错误发送至客户端。

在介绍依赖项与安全的章节中，您可以了解更多用 `raise` 异常代替 `return` 值的优势。

本例中，客户端用 `ID` 请求的 `item` 不存在时，触发状态码为 `404` 的异常：

```Python hl_lines="11"
{!../../docs_src/handling_errors/tutorial001.py!}

```

### 响应结果

请求为 `http://example.com/items/foo`（`item_id` 为 `「foo」`）时，客户端会接收到 HTTP 状态码 - 200 及如下 JSON 响应结果：

```JSON
{
  "item": "The Foo Wrestlers"