def get_list_of_types(stats):
    """
    Helper function to get list of types registered in stats

    Args:
        stats (dict): dictionary with statistics

    Returns:
        list: list of types registered

    """

    type_list = []
    for k, _ in stats.items():
        if k.type not in type_list:
            type_list.append(k.type)
    return type_list