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