code: def __feature_parser(self, uni_feature, word_surface):
          
          list_feature_items = uni_feature.split((','))
          # if word has no feature at all
          if len(list_feature_items)==1: return ('*'), ('*')
  
          pos1 = list_feature_items[0]
          pos2 = list_feature_items[1]
          pos3 = list_feature_items[2]
          tuple_pos = ( pos1, pos2, pos3 )
  
          # if without constraint(output is normal mecab dictionary like)
          if len(list_feature_items) == 9:
              word_stem = list_feature_items[6]
          # if with constraint(output format depends on Usedict.txt)
          else:
              word_stem = word_surface
  
          return tuple_pos, word_stem
docs: Parse the POS feature output by Mecab
          :param uni_feature unicode:
          :return ( (pos1, pos2, pos3), word_stem ):