code: def cut(self, text):
          
          remain = text
          while remain:
              matched = ''
              # 一次加一个字的匹配
              for index in range(len(remain)):
                  word = remain[:index + 1]
                  if word in self._prefix_set:
                      matched = word
                  else:
                      # 前面的字符串是个词语
                      if matched:
                          yield matched
                          matched = ''
                          remain = remain[index:]
                      else:  # 前面为空
                          yield word
                          remain = remain[index + 1:]
                      # 有结果了，剩余的重新开始匹配
                      break
              else:  # 整个文本就是一个词语
                  yield remain
                  break
docs: 分词
  
          :param text: 待分词的文本
          :yield: 单个词语