def get_sorted_idx(sub_dic):
    """
    Get the indices of each conformer ordered by ascending statistical weight.
    Args:
        sub_dic (dict): dictionary for a species
    Returns:
        sorted_idx (list): Sorted indices
    """

    confs = sub_dic["conformers"]
    weight_list = []
    for i, conf in enumerate(confs):
        weight_list.append([i, conf["boltzmannweight"]])
    sorted_tuples = sorted(weight_list, key=lambda x: -x[-1])
    sorted_idx = [i[0] for i in sorted_tuples]

    return sorted_idx