code: def _convert_consonant(sign):
          
          for key in TITTLES:
              sign = sign.replace(key, TITTLES[key])
          return sign
docs: Uses dictionary to replace ATF convention for unicode characters.
  
          input = ['as,', 'S,ATU', 'tet,', 'T,et', 'sza', 'ASZ']
          output = ['aṣ', 'ṢATU', 'teṭ', 'Ṭet', 'ša', 'AŠ']
  
          :param sign: string
          :return: string