For some inputs, there is error message when calling dimsim.get_candidates

[tbright17]

dimsim.get_candidates("大侠") works fine.
But when calling dimsim.get_candidates("龌龊"), it gives this error

Traceback (most recent call last):
  File "gen_sim_data.py", line 15, in <module>
    print(get_similar_phrase("龌龊"))
  File "gen_sim_data.py", line 8, in get_similar_phrase
    return dimsim.get_candidates(phrase, mode="simplified", theta=int(num_candid/2))[:-1]
  File "/usr/local/lib/python3.7/dist-packages/dimsim/core/model.py", line 80, in get_candidates
    candid = _get_close_pinyin_candids(word, theta)
  File "/usr/local/lib/python3.7/dist-packages/dimsim/core/model.py", line 109, in _get_close_pinyin_candids
    res.append(Pinyin(newPy))
  File "/usr/local/lib/python3.7/dist-packages/dimsim/utils/pinyin.py", line 15, in __init__
    self.pinyinRewrite()
  File "/usr/local/lib/python3.7/dist-packages/dimsim/utils/pinyin.py", line 41, in pinyinRewrite
    if 'v' in self.vowel:
TypeError: argument of type 'NoneType' is not iterable

any thoughts?

Thanks