Da wir zum Beispiel im `Image`-Modell ein Feld `url` haben, können wir deklarieren, dass das eine Instanz von Pydantics `HttpUrl` sein soll, anstelle eines `str`:

=== "Python 3.10+"

    ```Python hl_lines="2  8"
    {!> ../../../docs_src/body_nested_models/tutorial005_py310.py!}
    ```

=== "Python 3.9+"

but you might want to omit them from the result if they were not actually stored.

For example, if you have models with many optional attributes in a NoSQL database, but you don't want to send very long JSON responses full of default values.

### Use the `response_model_exclude_unset` parameter

You can set the *path operation decorator* parameter `response_model_exclude_unset=True`:

=== "Python 3.10+"

<div style="text-align: right; margin-right: 10%;">Kabir Khan - <strong>Microsoft</strong> <a href="https://github.com/tiangolo/fastapi/pull/26" target="_blank"><small>(ref)</small></a></div>

---

"_We adopted the **FastAPI** library to spawn a **REST** server that can be queried to obtain **predictions**. [for Ludwig]_"

<div style="text-align: right; margin-right: 10%;">Kabir Khan - <strong>Microsoft</strong> <a href="https://github.com/tiangolo/fastapi/pull/26" target="_blank"><small>(ref)</small></a></div>

---

"_Мы использовали библиотеку **FastAPI** для создания сервера **REST**, к которому можно делать запросы для получения **прогнозов**. [для Ludwig]_"

<div style="text-align: right; margin-right: 10%;">Kabir Khan - <strong>微软</strong> <a href="https://github.com/tiangolo/fastapi/pull/26" target="_blank"><small>(ref)</small></a></div>

---

「_我们选择了 **FastAPI** 来创建用于获取**预测结果**的 **REST** 服务。[用于 Ludwig]_」

                            "format": "email",
                        },
                        "full_name": IsDict(
                            {
                                "title": "Full Name",
                                "anyOf": [{"type": "string"}, {"type": "null"}],
                            }
                        )
                        | IsDict(

                    "properties": {
                        "username": {"title": "Username", "type": "string"},
                        "full_name": IsDict(
                            {
                                "title": "Full Name",
                                "anyOf": [{"type": "string"}, {"type": "null"}],
                            }
                        )
                        | IsDict(

                    "properties": {
                        "username": {"title": "Username", "type": "string"},
                        "full_name": IsDict(
                            {
                                "title": "Full Name",
                                "anyOf": [{"type": "string"}, {"type": "null"}],
                            }
                        )
                        | IsDict(

                                "anyOf": [{"type": "string"}, {"type": "null"}],
                            }
                        )
                        | IsDict(
                            # TODO: remove when deprecating Pydantic v1
                            {"title": "Full Name", "type": "string"}
                        ),
                        "disabled": IsDict(
                            {

                    "properties": {
                        "username": {"title": "Username", "type": "string"},
                        "full_name": IsDict(
                            {
                                "title": "Full Name",
                                "anyOf": [{"type": "string"}, {"type": "null"}],
                            }
                        )
                        | IsDict(