def _filter_result(result, filter_functions=None):
        """
        Filter result with given filter functions.

        :param result: an iterable object
        :param filter_functions: some filter functions
        :return: a filter object (filtered result)
        """
        if filter_functions is not None:
            for filter_func in filter_functions:
                result = filter(filter_func, result)
        return result
Filter result with given filter functions.

        :param result: an iterable object
        :param filter_functions: some filter functions
        :return: a filter object (filtered result)