code: def cut_for_search(self, sentence, HMM=True):
          
          words = self.cut(sentence, HMM=HMM)
          for w in words:
              if len(w) > 2:
                  for i in xrange(len(w) - 1):
                      gram2 = w[i:i + 2]
                      if self.FREQ.get(gram2):
                          yield gram2
              if len(w) > 3:
                  for i in xrange(len(w) - 2):
                      gram3 = w[i:i + 3]
                      if self.FREQ.get(gram3):
                          yield gram3
              yield w
docs: Finer segmentation for search engines.