code: def describe_instance_health(self, load_balancer_name, instances=None):
          
          params = {'LoadBalancerName' : load_balancer_name}
          if instances:
              self.build_list_params(params, instances,
                                     'Instances.member.%d.InstanceId')
          return self.get_list('DescribeInstanceHealth', params,
                               [('member', InstanceState)])
docs: Get current state of all Instances registered to an Load Balancer.
  
          :type load_balancer_name: string
          :param load_balancer_name: The name of the Load Balancer
  
          :type instances: List of strings
          :param instances: The instance ID's of the EC2 instances
                            to return status for.  If not provided,
                            the state of all instances will be returned.
  
          :rtype: List of :class:`boto.ec2.elb.instancestate.InstanceState`
          :return: list of state info for instances in this Load Balancer.