def register_instances(self, instances):
        if isinstance(instances, str) or isinstance(instances, unicode):
            instances = [instances]
        new_instances = self.connection.register_instances(self.name, instances)
        self.instances = new_instances
allows to restrict a given Settings object with the input of another Settings object
dataset/ETHPy150Open darcyliu/storyboard/boto/ec2/elb/loadbalancer.py/LoadBalancer.register_instances--crossover with--dataset/ETHPy150Open conan-io/conan/conans/model/settings.py/Settings.constraint