for prod and one for tests. However, unlike our other packages, as of this
    writing it has test supersource but no prod supersource.

    GWT happens to use the prod .gwt.xml, so it looks for no supersource for
    tests, either. This causes it to fail to find AtomicLongMapTest.

    Our workaround is to tell GWT that util.concurrent and all other packages

```

////

🎏 🕐❔ 📣 🔢 🔢, 🕐❔ 🏷 🔢 ✔️ 🔢 💲, ⚫️ 🚫 ✔. ⏪, ⚫️ ✔. ⚙️ `None` ⚒ ⚫️ 📦.

🖼, 👉 🏷 🔛 📣 🎻 "`object`" (⚖️ 🐍 `dict`) 💖:

```JSON
{
    "name": "Foo",
    "description": "An optional description",
    "price": 45.2,
    "tax": 3.5
}
```

... `description` & `tax` 📦 (⏮️ 🔢 💲 `None`), 👉 🎻 "`object`" 🔜 ☑:

```JSON
{
    "name": "Foo",
    "price": 45.2
}
```

from typing import Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Union[str, None] = Query(default=..., min_length=3)):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

## 📦 🔢

🎏 🌌, 👆 💪 📣 📦 🔢 🔢, ⚒ 👫 🔢 `None`:

//// tab | 🐍 3️⃣.6️⃣ & 🔛

```Python hl_lines="9"
{!> ../../docs_src/query_params/tutorial002.py!}
```

////

//// tab | 🐍 3️⃣.1️⃣0️⃣ & 🔛

```Python hl_lines="7"
{!> ../../docs_src/query_params/tutorial002_py310.py!}
```

////

👉 💼, 🔢 🔢 `q` 🔜 📦, & 🔜 `None` 🔢.

/// check

Fonksiyonunuzdaki parametre değerleri aşağıdaki gibi olacaktır:

* `skip=20`: çünkü bağlantıda böyle tanımlandı.
* `limit=10`: çünkü varsayılan değer buydu.

## İsteğe Bağlı Parametreler

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

//// tab | Python 3.10+

```Python hl_lines="7"
{!> ../../docs_src/query_params/tutorial002_py310.py!}
```

////

//// tab | Python 3.8+

from typing import Annotated, Union

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Annotated[Union[str, None], Query(min_length=3)] = ...):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})

     * Sie können deren URL mit dem Parameter `docs_url` festlegen.
     * Sie können sie deaktivieren, indem Sie `docs_url=None` festlegen.
* **ReDoc**: bereitgestellt unter `/redoc`.
     * Sie können deren URL mit dem Parameter `redoc_url` festlegen.
     * Sie können sie deaktivieren, indem Sie `redoc_url=None` festlegen.

{!../../docs_src/metadata/tutorial002.py!}
```

如果你想完全禁用 OpenAPI 模式，可以将其设置为 `openapi_url=None`，这样也会禁用使用它的文档用户界面。

## 文档 URLs

你可以配置两个文档用户界面，包括：

* **Swagger UI**：服务于 `/docs`。
    * 可以使用参数 `docs_url` 设置它的 URL。
    * 可以通过设置 `docs_url=None` 禁用它。
* ReDoc：服务于 `/redoc`。
    * 可以使用参数 `redoc_url` 设置它的 URL。
    * 可以通过设置 `redoc_url=None` 禁用它。

例如，设置 Swagger UI 服务于 `/documentation` 并禁用 ReDoc：

```Python hl_lines="3"

        {
            "detail": [
                {
                    "type": "missing",
                    "loc": ["body", "files"],
                    "msg": "Field required",
                    "input": None,
                }
            ]
        }
    ) | IsDict(
        # TODO: remove when deprecating Pydantic v1
        {
            "detail": [
                {
                    "loc": ["body", "files"],

from typing import Annotated

from fastapi import FastAPI, Query

app = FastAPI()


@app.get("/items/")
async def read_items(q: Annotated[str | None, Query(min_length=3)] = ...):
    results = {"items": [{"item_id": "Foo"}, {"item_id": "Bar"}]}
    if q:
        results.update({"q": q})