Because it's a Python exception, you don't `return` it, you `raise` it.

This also means that if you are inside a utility function that you are calling inside of your *path operation function*, and you raise the `HTTPException` from inside of that utility function, it won't run the rest of the code in the *path operation function*, it will terminate that request right away and send the HTTP error from the `HTTPException` to the client.

你不必為你使用到的每個標籤都加入中繼資料。

///

### 使用你的標籤 { #use-your-tags }

在你的路徑操作（以及 `APIRouter`s）上使用 `tags` 參數，將它們歸類到不同標籤下：

{* ../../docs_src/metadata/tutorial004_py310.py hl[21,26] *}

/// info | 資訊

在 [Path Operation Configuration](path-operation-configuration.md#tags) 中閱讀更多關於標籤的內容。

///

### 檢視文件 { #check-the-docs }

現在檢視文件時，會看到所有額外的中繼資料：

<img src="/img/tutorial/metadata/image02.png">

### 標籤順序 { #order-of-tags }

 * also defines an additional query operation, {@link #count}, which returns the count of an
 * element. There are five new bulk-modification operations, for example {@link #add(Object, int)},
 * to add or remove multiple occurrences of an element at once, or to set the count of an element to
 * a specific value. These modification operations are optional, but implementations which support

app = FastAPI()


@app.get("/items/")
async def read_items():
    return [{"item_id": "Foo"}]


def use_route_names_as_operation_ids(app: FastAPI) -> None:
    """
    Simplify operation IDs so that generated API clients have simpler function
    names.

    Should be called only after all routes have been added.
    """
    for route in app.routes:
        if isinstance(route, APIRoute):

///

### Path operation 関数 { #path-operation-functions }

*path operation 関数* を `async def` ではなく通常の `def` で宣言した場合、(サーバをブロックしてしまうため) 直接呼び出されるのではなく、外部のスレッドプールで実行され、それを待機します。

    - tutorial/handling-errors.md
    - tutorial/path-operation-configuration.md
    - tutorial/encoder.md
    - tutorial/body-updates.md
    - Dependencies:
      - tutorial/dependencies/index.md
      - tutorial/dependencies/classes-as-dependencies.md
      - tutorial/dependencies/sub-dependencies.md
      - tutorial/dependencies/dependencies-in-path-operation-decorators.md
      - tutorial/dependencies/global-dependencies.md

   * in a single load operation.
   */
  public double missRate() {
    long requestCount = requestCount();
    return (requestCount == 0) ? 0.0 : (double) missCount / requestCount;
  }

  /**
   * Returns the total number of times that {@link Cache} lookup methods attempted to load new
   * values. This includes both successful load operations and those that threw exceptions. This is

   * in a single load operation.
   */
  public double missRate() {
    long requestCount = requestCount();
    return (requestCount == 0) ? 0.0 : (double) missCount / requestCount;
  }

  /**
   * Returns the total number of times that {@link Cache} lookup methods attempted to load new
   * values. This includes both successful load operations and those that threw exceptions. This is

   * @deprecated Unsupported operation.
   */
  @Deprecated
  @Override
  @DoNotCall("Always throws UnsupportedOperationException")
  public void remove(Range<C> range) {
    throw new UnsupportedOperationException();
  }

  /**
   * Guaranteed to throw an exception and leave the {@code RangeSet} unmodified.
   *
   * @throws UnsupportedOperationException always
   * @deprecated Unsupported operation.
   */

  }

  /**
   * Returns an immutable copy of the provided table.
   *
   * <p>The {@link Table#cellSet()} iteration order of the provided table determines the iteration
   * ordering of all views in the returned table. Note that some views of the original table and the
   * copied table may have different iteration orders. For more control over the ordering, create a