def update_policy(self, scaling_group, policy, name=None, policy_type=None,
            cooldown=None, change=None, is_percent=False,
            desired_capacity=None, args=None):
        """
        Updates the specified policy. One or more of the parameters may be
        specified.
        """
        return self._manager.update_policy(scaling_group, policy, name=name,
                policy_type=policy_type, cooldown=cooldown, change=change,
                is_percent=is_percent, desired_capacity=desired_capacity,
                args=args)