docs: def most_similar(self, keyword, num):
          """
          input: keyword term of top n
          output: keyword result in json formmat
          """
          try:
              result = self.model.most_similar(keyword, topn = num) # most_similar return a list
              return {'key':keyword, 'value':result, 'similarity':1}
          except KeyError as e:
              kemKeyword = self.kemNgram.find(keyword)
              if kemKeyword:
                  result = self.model.most_similar(kemKeyword, topn = num)
                  return {'key':kemKeyword, 'value':result, 'similarity':self.kemNgram.compare(kemKeyword, keyword)}
              return {'key':keyword, 'value':[], 'similarity':0}