def METHOD_NAME(orig_dur: List[int],
                       pred_dur: List[int],
                       phns: List[str]):
    length = 0
    factor_list = []
    for orig, pred, phn in zip(orig_dur, pred_dur, phns):
        if pred == 0 or phn == 'sp':
            continue
        else:
            factor_list.append(orig / pred)
    factor_list = np.array(factor_list)
    factor_list.sort()
    if len(factor_list) < 5:
        return 1
    length = 2
    avg = np.average(factor_list[length:-length])
    return avg