if route.response_fields:
                responses_from_routes.extend(route.response_fields.values())
            if route.callbacks:
                callback_flat_models.extend(get_fields_from_routes(route.callbacks))
            params = get_flat_params(route.dependant)
            request_fields_from_routes.extend(params)

    flat_models = callback_flat_models + list(

        flat_dependant.path_params.extend(flat_sub.path_params)
        flat_dependant.query_params.extend(flat_sub.query_params)
        flat_dependant.header_params.extend(flat_sub.header_params)
        flat_dependant.cookie_params.extend(flat_sub.cookie_params)
        flat_dependant.body_params.extend(flat_sub.body_params)
        flat_dependant.dependencies.extend(flat_sub.dependencies)

    return flat_dependant

/// tip

This is a low level extension point.

If you only need to declare additional responses, a more convenient way to do it is with [Additional Responses in OpenAPI](additional-responses.md){.internal-link target=_blank}.

///

You can extend the OpenAPI schema for a *path operation* using the parameter `openapi_extra`.

            // The actual logic is tested in AbstractUpgradeGoalTest
            // Here we just verify that Apply is properly configured as a subclass
            assertInstanceOf(AbstractUpgradeGoal.class, applyGoal, "Apply should extend AbstractUpgradeGoal");
            assertTrue(applyGoal.shouldSaveModifications(), "Apply should save modifications unlike Check goal");
        }
    }

 * }</pre>
 *
 * <h2>Extension Points</h2>
 *
 * <p>To add new upgrade strategies:</p>
 * <ol>
 *   <li>Implement {@link org.apache.maven.cling.invoker.mvnup.goals.UpgradeStrategy}</li>
 *   <li>Optionally extend {@link org.apache.maven.cling.invoker.mvnup.goals.AbstractUpgradeStrategy}</li>
 *   <li>Annotate with {@code @Named} and {@code @Singleton}</li>
 *   <li>Use {@code @Priority} to control execution order</li>
 * </ol>
 *

                    current_tags.extend(tags)
                if route.tags:
                    current_tags.extend(route.tags)
                current_dependencies: list[params.Depends] = []
                if dependencies:
                    current_dependencies.extend(dependencies)
                if route.dependencies:
                    current_dependencies.extend(route.dependencies)

...and have the code for the tests just like before.

## Testing: extended example { #testing-extended-example }

Now let's extend this example and add more details to see how to test different parts.

### Extended **FastAPI** app file { #extended-fastapi-app-file }

Let's continue with the same file structure as before:

```
.
├── app
│   ├── __init__.py

    agent = Agent("openai:gpt-5.2")

    prompt_segments = [
        general_prompt,
        lang_prompt_content,
    ]
    if old_translation:
        prompt_segments.extend(
            [
                "There is an existing previous translation for the original English content, that may be outdated.",
                "Update the translation only where necessary:",

You can set `"json_schema_extra"` with a `dict` containing any additional data you would like to show up in the generated JSON Schema, including `examples`.

/// tip

You could use the same technique to extend the JSON Schema and add your own custom extra info.

For example you could use it to add metadata for a frontend user interface, etc.

///

/// info

</li>

<li>
<code>R0.UXTB</code>
<br>
<code>R0.UXTB&lt;&lt;imm</code>:
<code>UXTB</code>: extract an 8-bit value from the low-order bits of <code>R0</code> and zero-extend it to the size of <code>R0</code>.
<code>R0.UXTB&lt;&lt;imm</code>: left shift the result of <code>R0.UXTB</code> by <code>imm</code> bits.
The <code>imm</code> value can be 0, 1, 2, 3, or 4.