code: def get_top_n(self):
          ''' getter '''
          if isinstance(self.__top_n, int) is False:
              raise TypeError("The type of __top_n must be int.")
          return self.__top_f get_top_n(self):
          ''' getter '''
          if isinstance(self.__top_n, int) is False:
              raise TypeError("The type of __top_n must be int.")
          return self.__top_n
docs: getter