code: def add_lb_secgroup(self, lb_name, hosts, port):
          
          self.lb_sec_groups.merge(lb_name, {'hosts': hosts, 'port': port})
docs: Used by the load balancer deployer to register a hostname
          for a load balancer, in order that security group rules can be
          applied later. This is multiprocess-safe, but since keys are
          accessed only be a single load balancer deployer there should be
          no conflicts.
  
          :param str lb_name: The load balancer name (as per the config file)
  
          :param :class:`list` hosts:  The load balancer host[s], once known
  
          :param port:  The backend port that the LB will connect on