code: def listener_create_event(self, listener_info):
          
          listener_data = listener_info.get('listener')
          lb_list = listener_data.get('loadbalancers')
          for lb in lb_list:
              lb_id = lb.get('id')
              req = dict(instance_id=(lb_id.replace('-', '')))
              instances = self.get_vms_for_this_req(**req)
              if not instances:
                  lb_info = self.neutronclient.show_loadbalancer(lb_id)
                  if lb_info:
                      port_id = lb_info["loadbalancer"]["vip_port_id"]
                      self.add_lbaas_port(port_id, lb_id)
              else:
                  LOG.info("lbaas port for lb %s already added" % lb_id)
docs: Process listener create event.
  
          This is lbaas v2
          vif will be plugged into ovs when first
          listener is created and unpluged from ovs
          when last listener is deleted