def __missing__(self, key):
        if self.default_factory is None:
            raise KeyError(key)
        else:
            ret = self[key] = self.default_factory(name=key)
            return ret
def __normalize_probabilities(self):
        for index_point in range(len(self.__data)):
            probability = 0.0
            for index_cluster in range(len(self.__clusters)):
                probability += self.__rc[index_cluster][index_point]