```Python
with open("file.txt") as file:
    file.read()
```

В последних версиях Python есть также асинхронный менеджер контекста. Его используют с `async with`:

```Python
async with lifespan(app):
    await do_stuff()
```

Когда вы создаёте менеджер контекста или асинхронный менеджер контекста, как выше, он перед входом в блок `with` выполнит код до `yield`, а после выхода из блока `with` выполнит код после `yield`.

    }
  }

  override fun cancel() {
    delegate.cancel()
  }

  override fun close() {
    javaNetSocket.close()
  }

  fun awaitClosed() {
    closedLatch.await()
  }

    file.read()
```

Dans les versions récentes de Python, il existe aussi un **gestionnaire de contexte asynchrone**. Vous l'utiliseriez avec `async with` :

```Python
async with lifespan(app):
    await do_stuff()
```

    (this as Object).notifyAll()
  }

  /**
   * Returns the recorded response triggered by `request`. Throws if the response isn't
   * enqueued before the timeout.
   */
  @Synchronized
  fun await(url: HttpUrl): RecordedResponse {
    val timeoutMillis = TimeUnit.NANOSECONDS.toMillis(System.nanoTime()) + TIMEOUT_MILLIS
    while (true) {
      val i = responses.iterator()
      while (i.hasNext()) {

        AtomicInteger customThreadFound = new AtomicInteger(0);

        // Create a custom thread with recognizable name
        Thread customThread = new Thread(() -> {
            try {
                latch.await();
            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            }
        }, "CustomTestThread");

        customThread.start();

        try {

with open("file.txt") as file:
    file.read()
```

In neueren Versionen von Python gibt es auch einen **asynchronen Kontextmanager**. Sie würden ihn mit `async with` verwenden:

```Python
async with lifespan(app):
    await do_stuff()
```

        final List<String> allUrls = new ArrayList<>();

        for (int i = 0; i < numThreads; i++) {
            new Thread(() -> {
                try {
                    startLatch.await();
                    int count = 0;
                    while (count < itemsPerThread) {
                        final OpenSearchUrlQueue polled = urlQueueService.poll(sessionId);

      Producer producer = new Producer(q, 1);
      // producing one, will ask for two
      Future<?> producerThread = threadPool.submit(producer);
      producer.beganProducing.await();

      // make sure we time out
      Stopwatch timer = Stopwatch.createStarted();

      int drained = drain(q, new ArrayList<>(), 2, 10, MILLISECONDS, interruptibly);
      assertThat(drained).isAtMost(1);

  override fun ensureLoaded() {
    if (!listRead.get() && listRead.compareAndSet(false, true)) {
      readTheListUninterruptibly()
    } else {
      try {
        readCompleteLatch.await()
      } catch (_: InterruptedException) {
        Thread.currentThread().interrupt() // Retain interrupted status.
      }
    }

    if (!::bytes.isInitialized) {
      // May have failed with an IOException

    Her zaman olduğu gibi, FastAPI'de ihtiyaca göre `def` ve `async def`’i birlikte kullanabilirsiniz.

    Hangisini ne zaman kullanmanız gerektiğine dair hızlı bir hatırlatma isterseniz, [`async` ve `await`](../async.md#in-a-hurry) dokümanındaki _"In a hurry?"_ bölümüne bakın.

9. Bu *path operation function* dataclass döndürmüyor (isterse döndürebilir), onun yerine dahili verilerle bir dictionary listesi döndürüyor.