"include-optional-dependencies", []
    )
    # Override main [project] configs with custom configs for this package
    for key, value in project_config.items():
        metadata[key] = value
    # Get custom build config for the current package
    build_config: Dict[str, Any] = (
        config.get("tool", {}).get("pdm", {}).get("build", {})
    )
    # Override PDM build config with custom build config for this package

        * [Install custom exception handlers](https://fastapi.tiangolo.com/tutorial/handling-errors/#install-custom-exception-handlers).
        * [Override the default exception handlers](https://fastapi.tiangolo.com/tutorial/handling-errors/#override-the-default-exception-handlers).
        * [Re-use **FastAPI's** exception handlers](https://fastapi.tiangolo.com/tutorial/handling-errors/#re-use-fastapis-exception-handlers).

    ```

### Settings and testing

Then it would be very easy to provide a different settings object during testing by creating a dependency override for `get_settings`:

```Python hl_lines="9-10  13  21"
{!../../../docs_src/settings/app02/test_main.py!}
```

In the dependency override we set a new value for the `admin_email` when creating the new `Settings` object, and then we return that new object.

When a **container** is started, it will run that command/program (although you can override it and make it run a different command/program).

A container is running as long as the **main process** (command or program) is running.