'Sets the default gateway for this dhcp namespace.
This method is idempotent and will only adjust the route if adjusting
it would change it from what it already is.  This makes it safe to call
and avoids unnecessary perturbation of the system.'

def _set_default_route(self, network, device_name):

    for ip_version in (constants.IP_VERSION_4, constants.IP_VERSION_6):
        self._set_default_route_ip_version(network, device_name, ip_version)
