def METHOD_NAME(experiment_id, filename):
    # type: (str, str) -> None
    """
    Generate CSV with all runs for an experiment
    """
    runs = fluent.search_runs(experiment_ids=experiment_id)
    if filename:
        runs.to_csv(filename, index=False)
        click.echo(
            f"Experiment with ID {experiment_id} has been exported as a CSV to file: {filename}."
        )
    else:
        click.echo(runs.to_csv(index=False))