```Python hl_lines="7"
    {!> ../../../docs_src/query_params_str_validations/tutorial006c_py310.py!}
    ```

!!! tip
    Pydantic, ❔ ⚫️❔ 🏋️ 🌐 💽 🔬 &amp; 🛠️ FastAPI, ✔️ 🎁 🎭 🕐❔ 👆 ⚙️ `Optional` ⚖️ `Union[Something, None]` 🍵 🔢 💲, 👆 💪 ✍ 🌅 🔃 ⚫️ Pydantic 🩺 🔃 <a href="https://docs.pydantic.dev/latest/concepts/models/#required-optional-fields" class="external-link" target="_blank">✔ 📦 🏑</a>.

### ⚙️ Pydantic `Required` ↩️ ❕ (`...`)

def test_get_exception():
    response = client.get("/unicorns/yolo")
    assert response.status_code == 418, response.text
    assert response.json() == {
        "message": "Oops! yolo did something. There goes a rainbow..."
    }


def test_openapi_schema():
    response = client.get("/openapi.json")
    assert response.status_code == 200, response.text
    assert response.json() == {

Когда вы добавляете пример внутрь модели Pydantic, используя `schema_extra` или `Field(example="something")`, этот пример добавляется в **JSON Schema** для данной модели Pydantic.

И эта **JSON Schema** модели Pydantic включается в **OpenAPI** вашего API, а затем используется в UI документации.

Ein „**Callable**“ in Python ist etwas, das wie eine Funktion aufgerufen werden kann („to call“).

Wenn Sie also ein Objekt `something` haben (das möglicherweise _keine_ Funktion ist) und Sie es wie folgt aufrufen (ausführen) können:

```Python
something()
```

oder

```Python
something(some_argument, some_keyword_argument="foo")
```

dann ist das ein „Callable“ (ein „Aufrufbares“).

## Klassen als Abhängigkeiten

    assert "email" in data[0]
    assert "id" in data[0]


# TODO: pv2 add Pydantic v2 version
@needs_pydanticv1
def test_create_item(client):
    item = {"title": "Foo", "description": "Something that fights"}
    response = client.post("/users/1/items/", json=item)
    assert response.status_code == 200, response.text
    item_data = response.json()
    assert item["title"] == item_data["title"]

    assert "email" in data[0]
    assert "id" in data[0]


@needs_py310
# TODO: pv2 add Pydantic v2 version
@needs_pydanticv1
def test_create_item(client):
    item = {"title": "Foo", "description": "Something that fights"}
    response = client.post("/users/1/items/", json=item)
    assert response.status_code == 200, response.text
    item_data = response.json()
    assert item["title"] == item_data["title"]

```

</div>

## Check it

Go to the interactive docs at: <a href="http://127.0.0.1:8000/docs" class="external-link" target="_blank">http://127.0.0.1:8000/docs</a>.

You will see something like this:

<img src="/img/tutorial/security/image01.png">

!!! check "Authorize button!"
    You already have a shiny new "Authorize" button.

### Async Context Manager

If you check, the function is decorated with an `@asynccontextmanager`.

That converts the function into something called an "**async context manager**".

```Python hl_lines="1  13"
{!../../../docs_src/events/tutorial003.py!}
```

A **context manager** in Python is something that you can use in a `with` statement, for example, `open()` can be used as a context manager:

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

!!! tip
    The actual callback is just an HTTP request.

    When implementing the callback yourself, you could use something like <a href="https://www.python-httpx.org" class="external-link" target="_blank">HTTPX</a> or <a href="https://requests.readthedocs.io/" class="external-link" target="_blank">Requests</a>.

## Write the callback documentation code

{!../../../docs_src/python_types/tutorial009.py!}
```

⚙️ `Optional[str]` ↩️ `str` 🔜 ➡️ 👨‍🎨 ℹ 👆 🔍 ❌ 🌐❔ 👆 💪 🤔 👈 💲 🕧 `str`, 🕐❔ ⚫️ 💪 🤙 `None` 💁‍♂️.

`Optional[Something]` 🤙 ⌨ `Union[Something, None]`, 👫 🌓.

👉 ⛓ 👈 🐍 3️⃣.1️⃣0️⃣, 👆 💪 ⚙️ `Something | None`:

=== "🐍 3️⃣.6️⃣ & 🔛"

    ```Python hl_lines="1  4"
    {!> ../../../docs_src/python_types/tutorial009.py!}
    ```