protected AbstractIterator() {}

  private enum State {
    READY,
    NOT_READY,
    DONE,
    FAILED,
  }

  private @Nullable T next;

  protected abstract @Nullable T computeNext();

  @CanIgnoreReturnValue
  protected final @Nullable T endOfData() {
    state = State.DONE;
    return null;
  }

  @Override
  public final boolean hasNext() {
    checkState(state != State.FAILED);

http://127.0.0.1:8000/items/?skip=20
```

🔢 💲 👆 🔢 🔜:

* `skip=20`: ↩️ 👆 ⚒ ⚫️ 📛
* `limit=10`: ↩️ 👈 🔢 💲

## 📦 🔢

🎏 🌌, 👆 💪 📣 📦 🔢 🔢, ⚒ 👫 🔢 `None`:

{* ../../docs_src/query_params/tutorial002.py hl[9] *}

👉 💼, 🔢 🔢 `q` 🔜 📦, & 🔜 `None` 🔢.

/// check

👀 👈 **FastAPI** 🙃 🥃 👀 👈 ➡ 🔢 `item_id` ➡ 🔢 & `q` 🚫,, ⚫️ 🔢 🔢.

///

## 🔢 🔢 🆎 🛠️

/// note | Nota

FastAPI sabrá que el valor de `q` no es requerido debido al valor por defecto `= None`.

El `str | None` (Python 3.10+) o `Union` en `Union[str, None]` (Python 3.8+) no es utilizado por FastAPI para determinar que el valor no es requerido, sabrá que no es requerido porque tiene un valor por defecto de `= None`.

Pero agregar las anotaciones de tipos permitirá que tu editor te brinde un mejor soporte y detecte errores.

```

`Optional[str]` ব্যবহার করা মানে হল শুধু `str` নয়, এটি হতে পারে `None`-ও, যা আপনার এডিটরকে সেই ত্রুটিগুলি শনাক্ত করতে সাহায্য করবে যেখানে আপনি ধরে নিচ্ছেন যে একটি মান সবসময় `str` হবে, অথচ এটি `None`-ও হতে পারেও।

`Optional[Something]` মূলত `Union[Something, None]`-এর একটি শর্টকাট, এবং তারা সমতুল্য।

এর মানে হল, Python 3.10-এ, আপনি টাইপগুলির ইউনিয়ন ঘোষণা করতে `Something | None` ব্যবহার করতে পারেন:

//// tab | Python 3.10+

Da einfache Werte standardmäßig als Query-Parameter interpretiert werden, müssen Sie `Query` nicht explizit hinzufügen, Sie können einfach schreiben:

```Python
q: Union[str, None] = None
```

Oder in Python 3.10 und darüber:

```Python
q: str | None = None
```

Zum Beispiel:

{* ../../docs_src/body_multiple_params/tutorial004_an_py310.py hl[27] *}

/// info

	rv=$?

	pkill minio
	sleep 3

	if [ "$rv" -ne 0 ]; then
		for i in $(seq 0 1); do
			echo "server$i log:"
			cat "$WORK_DIR/pool-minio-900$i.log"
		done
	fi

	for i in $(seq 0 1); do
		rm -f "$WORK_DIR/pool-minio-900$i.log"
	done

	return "$rv"
}

function run_test_pool_erasure_sets_ipv6() {
	start_minio_pool_erasure_sets_ipv6

	export SERVER_ENDPOINT="[::1]:9000"

	return errorResponseHandler
}

// If none of the http routes match respond with appropriate errors
func errorResponseHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method == http.MethodOptions {
		return
	}

* `limit=10`: çünkü varsayılan değer buydu.

## İsteğe Bağlı Parametreler

Aynı şekilde, varsayılan değerlerini `None` olarak atayarak isteğe bağlı parametreler tanımlayabilirsiniz:

{* ../../docs_src/query_params/tutorial002_py310.py hl[7] *}

Bu durumda, `q` fonksiyon parametresi isteğe bağlı olacak ve varsayılan değer olarak `None` alacaktır.

/// check | Ek bilgi

    assertThat(expected).hasMessageThat().contains("one");
  }

  public void testOf() {
    assertMapEquals(ImmutableBiMap.of("one", 1), "one", 1);
    assertMapEquals(ImmutableBiMap.of("one", 1).inverse(), 1, "one");
    assertMapEquals(ImmutableBiMap.of("one", 1, "two", 2), "one", 1, "two", 2);
    assertMapEquals(ImmutableBiMap.of("one", 1, "two", 2).inverse(), 1, "one", 2, "two");
    assertMapEquals(

## 선택적 매개변수

같은 방법으로 기본값을 `None`으로 설정하여 선택적 매개변수를 선언할 수 있습니다:

{* ../../docs_src/query_params/tutorial002.py hl[9] *}

이 경우 함수 매개변수 `q`는 선택적이며 기본값으로 `None` 값이 됩니다.

/// check | 확인

**FastAPI**는 `item_id`가 경로 매개변수이고 `q`는 경로 매개변수가 아닌 쿼리 매개변수라는 것을 알 정도로 충분히 똑똑합니다.

///

/// note | 참고

FastAPI는 `q`가 `= None`이므로 선택적이라는 것을 인지합니다.