'Get a provider driver handle for a given flavor_id.'

def _get_l3_driver_by_flavor(self, context, flavor_id):

    flavor = self._flavor_plugin.get_flavor(context, flavor_id)
    provider = self._flavor_plugin.get_flavor_next_provider(context, flavor['id'])[0]
    driver = self.drivers[provider['provider']]
    return driver
