def get_run_stats_filepath(session_path, agent_id, eval=False):
    """ Gets the filepath to the run statistics file."""

    stats_dir = session_path / 'monitor'
    stats_dir.mkdir(exist_ok=True)

    if eval:
        return stats_dir / 'eval.csv'
    else:
        return stats_dir / f'agent_{agent_id}.csv'