def list_config_variables(self, offset):
        """List defined config variables up to 9 at a time."""

        names = sorted(self._config_variables)
        names = names[offset:offset + 9]
        count = len(names)

        if len(names) < 9:
            names += [0]*(9 - count)

        return [count] + names
List defined config variables up to 9 at a time.