def read_item(item_id: int, q: Union[str, None] = None):
    return {"item_id": item_id, "q": q}
```

<details markdown="1">
<summary>或者使用 <code>async def</code>...</summary>

如果你的代码里会出现 `async` / `await`，请使用 `async def`：

```Python hl_lines="9  14"
from typing import Union

from fastapi import FastAPI

app = FastAPI()


@app.get("/")
async def read_root():
    return {"Hello": "World"}

./mc cp README.md myminio1/foobucket/dir/file

versionId="$(./mc ls --json --versions myminio1/foobucket/dir/ | jq -r .versionId)"

kill ${pid2} && wait ${pid2} || true

aws s3api --endpoint-url http://localhost:9001 delete-object --bucket foobucket --key dir/file --version-id "$versionId"

out="$(./mc ls myminio1/foobucket/dir/)"
if [ "$out" != "" ]; then

        new UncaughtExceptionHandler() {
          @Override
          public void uncaughtException(Thread t, Throwable e) {}
        });
    thread.start();

    boolean done = doneSignal.await(1, SECONDS);
    if (!done) {
      StringBuilder builder = new StringBuilder();
      for (StackTraceElement trace : thread.getStackTrace()) {
        builder.append("\tat ").append(trace).append('\n');
      }

## タスク関数の作成

バックグラウンドタスクとして実行される関数を作成します。

これは、パラメーターを受け取ることができる単なる標準的な関数です。

これは `async def` または通常の `def` 関数であり、**FastAPI** はこれを正しく処理します。

ここで、タスク関数はファイル書き込みを実行します (メール送信のシミュレーション)。

また、書き込み操作では `async` と `await` を使用しないため、通常の `def` で関数を定義します。

{* ../../docs_src/background_tasks/tutorial001.py hl[6:9] *}

## バックグラウンドタスクの追加

*path operations 関数* 内で、`.add_task()` メソッドを使用してタスク関数を *background tasks* オブジェクトに渡します。

        try {
            rateLimiter.checkAttempt(username, ip);
            fail("Should be locked out");
        } catch (SmbException e) {
            // Expected
        }

        // Wait for lockout to expire
        Thread.sleep(2100); // Lockout is 2 seconds in test setup

        // Should be allowed again
        assertTrue(rateLimiter.checkAttempt(username, ip), "Should be allowed after lockout expiry");

		return nil, err
	}

	return obj, nil
}

// TransferError will catch network errors during transfer.
// When TransferError() is called Close() will also
// be called, so we do not need to Wait() here.
func (w *writerAt) TransferError(err error) {
	_ = w.w.CloseWithError(err)
	_ = w.r.CloseWithError(err)
	w.err = err
}

func (w *writerAt) Close() (err error) {
	switch {

            return "Free up disk space or use a different location";
        case QUOTA:
            return "Contact administrator to increase quota limits";
        case LOCK:
            return "Release existing locks or wait for them to be released";
        case BUFFER:
            return "Reduce buffer usage or increase buffer pool size";
        case THREAD_POOL:
            return "Reduce concurrent operations or increase thread pool size";

2. Start Prometheus server and AlertManager
3. Bring down couple of MinIO instances to bring down the Erasure Set tolerance to -1 and verify the same with `mc admin prometheus metrics ALIAS | grep minio_cluster_health_erasure_set_status`
4. Wait for 5 mins (as alert is configured to be firing after 5 mins), and verify that you see an entry in webhook for the alert as well as in Prometheus console as shown below

```json
{
  "receiver": "web\\.hook",

    /**
     * Context object containing crawler state and configuration.
     */
    protected CrawlerContext crawlerContext;

    /**
     * Flag indicating whether to wait on folder operations.
     */
    protected boolean noWaitOnFolder = false;

    /**
     * Increments the active thread count.
     */
    protected void startCrawling() {

            }
        }
    }

    /**
     * Interrupts the thread and waits for it to terminate.
     *
     * @param timeoutMillis
     *            The time to wait (in milliseconds)
     * @return <code>true</code> if the thread has terminated
     * @throws InterruptedException
     *             If interrupted while waiting
     */