* 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. ✨

            Doc(
                """
                The version of the API.

                **Note** This is the version of your application, not the version of
                the OpenAPI specification nor the version of FastAPI being used.

                It will be added to the generated OpenAPI (e.g. visible at `/docs`).

                Read more in the

     * 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