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
:param FilePath directory: Directory where the certificates can be
dataset/ETHPy150Open radlab/sparrow/deploy/third_party/boto-2.1.1/boto/ec2/elb/loadbalancer.py/LoadBalancer.register_instances--crossover with--dataset/ETHPy150Open ClusterHQ/flocker/flocker/provision/_ca.py/Certificates.__init__