def deregister_instances(self, instances):
        if isinstance(instances, str) or isinstance(instances, unicode):
            instances = [instances]
        new_instances = self.connection.deregister_instances(self.name, instances)
        self.instances = new_instances
Ensures that the contact is not removed if it's failedRPCs counter is
dataset/ETHPy150Open radlab/sparrow/deploy/third_party/boto-2.1.1/boto/ec2/elb/loadbalancer.py/LoadBalancer.deregister_instances--crossover with--dataset/ETHPy150Open ntoll/p4p2p/test/dht/test_routingtable.py/TestRoutingTable.test_remove_contact_with_not_enough_RPC_fails