* creator of the problem, the general expectation is that the hint provides sufficient information to the user to
     * track the problem back to its origin. A concrete example for such a source hint can be the file path or URL from
     * which the settings were read.
     *
     * @return The hint about the source of the problem or an empty string if unknown, never {@code null}.
     */
    String getSource();

    /**

     * build the model for a POM from the repository, use {@link #setModelSource(ModelSource)} in combination with a
     * {@link FileModelSource} instead.
     *
     * @param pomFile The POM file of the project to build the effective model for, may be {@code null} to build the
     *            model of some POM from the repository.
     * @return This request, never {@code null}.

    /**
     * Attaches a produced artifact to the project at the specified path. This is the base method
     * that the other attachArtifact methods delegate to.
     *
     * @param project the project to attach the artifact to
     * @param artifact the produced artifact to attach
     * @param path the path to the artifact file
     * @throws IllegalArgumentException if the project, artifact or path is null
     */

    }

    /**
     * Gets the one-based index of the line containing the error.
     *
     * @return The one-based index of the line containing the error or a non-positive value if unknown.
     */
    public int getLineNumber() {
        return lineNumber;
    }

    /**
     * Gets the one-based index of the column containing the error.
     *

### Include the custom docs

Now you can create the *path operations* for the custom docs.

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.

That demonstrates how the Proxy (Traefik) uses the path prefix and how the server (Uvicorn) uses the `root_path` from the option `--root-path`.

### Check the docs UI

But here's the fun part. ✨

     * reference. If the cached data is mutable, i.e. could be modified after being put into the cache, the caller is
     * responsible for creating a copy of the original data and store the copy in the cache.
     *
     * @param request The repository request from which this cache was retrieved, must not be {@code null}.
     * @param key The key to use associate the data with, must not be {@code null}.

</details>

Here we use the `SessionDep` dependency (a `Session`) to add the new `Hero` to the `Session` instance, commit the changes to the database, refresh the data in the `hero`, and then return it.

### Read Heroes

We can **read** `Hero`s from the database using a `select()`. We can include a `limit` and `offset` to paginate the results.

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[48:55] hl[51:52,54] *}

So, what we will do next is add the code to document how that *external API* should look like to receive the callback from *your API*.

That documentation will show up in the Swagger UI at `/docs` in your API, and it will let external developers know how to build the *external API*.

This example doesn't implement the callback itself (that could be just a line of code), only the documentation part.

/// tip

     *
     * @param message The detail message, may be {@code null}.
     * @param groupId The group id of the unresolvable model, may be {@code null}.
     * @param artifactId The artifact id of the unresolvable model, may be {@code null}.
     * @param version The version of the unresolvable model, may be {@code null}.
     * @param cause The cause, may be {@code null}.
     */
    public UnresolvableModelException(