code: public static List<Pinyin> makeToneToTheSame(List<Pinyin> pinyinList)
      {
          ListIterator<Pinyin> listIterator = pinyinList.listIterator();
          while (listIterator.hasNext())
          {
              listIterator.set(convert2Tone5(listIterator.next()));
          }
  
          return pinyinList;
      }
docs: 将所有音调都转为1
  @param pinyinList
  @return