def summary_stats(model_result_dict: dict) -> dict:
    """Summary statistics can be used to convert raw model output (created by the my_model() function)
    to summary information. This is then passed to the distance() function (see below).
    Summary stats are optional as the distance() function can always convert the raw output to a summary,
    but anything included in the dictionary returned by this function *is added to the results database*.
    This can be really useful e.g. for storing the state of a particular model. The data can be retrieved
    from the database with `abc_history.get_population_extended()`, which returns a DataFrame.
    (Here all the function does is return the model raw model results, but includes an additional
    dictionary item 'test'."""
    # 'model_result' was the key in the dict defined in my_model
    model_result_summary = model_result_dict['model_result']
    return {"model_summary": model_result_summary, "test": "SUMMARY_TEST"}