code: def delete_security_group_rule(context, id):
      
      LOG.info("delete_security_group %s for tenant %s" %
               (id, context.tenant_id))
      with context.session.begin():
          rule = db_api.security_group_rule_find(context, id=id,
                                                 scope=db_api.ONE)
          if not rule:
              raise sg_ext.SecurityGroupRuleNotFound(id=id)
  
          group = db_api.security_group_find(context, id=rule["group_id"],
                                             scope=db_api.ONE)
          if not group:
              raise sg_ext.SecurityGroupNotFound(id=id)
  
          rule["id"] = id
          db_api.security_group_rule_delete(context, rule)
      if group:
          _perform_async_update_rule(context, group.id, group, id, RULE_DELETE)
docs: Deletes a rule and updates the ports (async) if enabled.