```JSON
{"item_id":3}
```

!!! check
    Notice that the value your function received (and returned) is `3`, as a Python `int`, not a string `"3"`.

    So, with that type declaration, **FastAPI** gives you automatic request <abbr title="converting the string that comes from an HTTP request into Python data">"parsing"</abbr>.

## Data validation

    ```

## Set-Typen

Aber dann denken wir darüber nach und stellen fest, dass sich die Tags nicht wiederholen sollen, es sollen eindeutige Strings sein.

Python hat einen Datentyp speziell für Mengen eindeutiger Dinge: das <abbr title="Menge">`set`</abbr>.

Deklarieren wir also `tags` als Set von Strings.

=== "Python 3.10+"

    ```Python hl_lines="12"
    {!> ../../../docs_src/body_nested_models/tutorial003_py310.py!}
    ```

![Swagger UI interaction](https://fastapi.tiangolo.com/img/index/index-03-swagger-02.png)

* Thay thế với tài liệu API với <a href="https://github.com/Rebilly/ReDoc" class="external-link" target="_blank"><strong>ReDoc</strong></a>.

👆 💪 ⚒ 👫 ⏩:

---

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

---

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

                                    "maxLength": 50,
                                    "minLength": 3,
                                    "pattern": "^fixedquery$",
                                    "type": "string",
                                    "description": "Query string for the items to search in the database that have a good match",
                                }
                            ),

                                "type": "string",
                            }
                        ),
                        "username": {"title": "Username", "type": "string"},
                        "password": {"title": "Password", "type": "string"},
                        "scope": {"title": "Scope", "type": "string", "default": ""},
                        "client_id": IsDict(

        This dependency is strict about it. If you want to be permissive, use instead the
        OAuth2PasswordRequestForm dependency class.
    username: username string. The OAuth2 spec requires the exact field name "username".
    password: password string. The OAuth2 spec requires the exact field name "password".

                            "items": {
                                "anyOf": [{"type": "string"}, {"type": "integer"}]
                            },
                        },
                        "msg": {"title": "Message", "type": "string"},
                        "type": {"title": "Error Type", "type": "string"},
                    },
                },
                "HTTPValidationError": {