KeyError: 'ᆶ'

[lyger]

Hi, I'm processing some multilingual data, but I'm afraid I don't actually know Korean myself. I'm getting an error on this word. I don't know if the word is written incorrectly (if so, how should it be fixed?), or if it's a problem in the library. Any help would be appreciated.

korean_romanizer.Romanizer('뚫리고').romanize()
---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
<ipython-input-40-769d5465ca1f> in <module>
----> 1 korean_romanizer.Romanizer('뚫리고').romanize()

c:\program files\python37\lib\site-packages\korean_romanizer\romanizer.py in romanize(self)
    121                 else:
    122                     # s is a full syllable
--> 123                     _romanized += onset[s.initial] + vowel[s.medial] + coda[s.final]
    124 
    125             else:

KeyError: 'ᆶ'