Remember that when you import `Query`, `Path`, and others from `fastapi`, those are actually functions that return special classes.

///

/// tip

Notice how each model's attribute with a type, default value and `Field` has the same structure as a *path operation function's* parameter, with `Field` instead of `Path`, `Query` and `Body`.

///

## Add extra information { #add-extra-information }

### Usa el atributo `app.dependency_overrides` { #use-the-app-dependency-overrides-attribute }

Para estos casos, tu aplicación **FastAPI** tiene un atributo `app.dependency_overrides`, es un simple `dict`.

    // ===================================================================================
    //                                                                           Attribute
    //                                                                           =========
    /** createdTime */
    protected Long createdTime;

    /** expiredTime */
    protected Long expiredTime;

    // ===================================================================================
    //                                                                           Attribute
    //                                                                           =========
    /** crawlingInfoId */
    protected String crawlingInfoId;

    /** createdTime */
    protected Long createdTime;

 * saml.sp.base.url=https://your-fess-server.example.com
 * </pre>
 *
 * <h2>Optional Configuration</h2>
 * <pre>
 * # User attribute mapping
 * saml.attribute.group.name=groups
 * saml.attribute.role.name=roles
 *
 * # Default groups/roles for authenticated users
 * saml.default.groups=user
 * saml.default.roles=user
 * </pre>
 *

        super();
    }

    // ===================================================================================
    //                                                                           Attribute
    //                                                                           =========

    /** The user service for managing user settings. */
    @Resource
    private UserService userService;

    /**

Now use the parameter `callbacks` in *your API's path operation decorator* to pass the attribute `.routes` (that's actually just a `list` of routes/*path operations*) from that callback router:

{* ../../docs_src/openapi_callbacks/tutorial001_py310.py hl[33] *}

/// tip

Notice that you are not passing the router itself (`invoices_callback_router`) to `callback=`, but the attribute `.routes`, as in `invoices_callback_router.routes`.

///

You can reuse FastAPI's internal functions to create the HTML pages for the docs, and pass them the needed arguments:

* `openapi_url`: the URL where the HTML page for the docs can get the OpenAPI schema for your API. You can use here the attribute `app.openapi_url`.
* `title`: the title of your API.
* `oauth2_redirect_url`: you can use `app.swagger_ui_oauth2_redirect_url` here to use the default.

    // ===================================================================================
    //                                                                           Attribute
    //                                                                           =========
    /** createdAt */
    protected LocalDateTime createdAt;

    /** docId */
    protected String docId;

    private final FessUser user;

    // ===================================================================================
    //                                                                           Attribute
    //                                                                           =========

    // ===================================================================================