code: def update_default_rules(self):
          
          app_ingress = self.properties['security_group']['ingress']
          ingress = conservative_merger.merge(DEFAULT_SECURITYGROUP_RULES, app_ingress)
          resolved_ingress = self.resolve_self_references(ingress)
          self.log.info('Updated default rules:\n%s', ingress)
          return resolved_ingress
docs: Concatinate application and global security group rules.