def total_duration(final_note_list):
    """
        To compute total duration from the SCAMP note list supplied
        @param final_note_list: SCAMP notes list [ "Carntic Note", ["Instrument", "Volume", "Duration"], ...]
        @return: total duration
    """
    sum = 0.0
    for note in final_note_list:
        [_,[_,_,durn]] = note
        sum += durn
    return sum