def self.delete_subnet_group(subnet_group_id, region: MU.curRegion, credentials: nil)
          retries ||= 0
          MU.log "Deleting Subnet group #{subnet_group_id}"
          MU::Cloud::AWS.elasticache(region: region, credentials: credentials).delete_cache_subnet_group(cache_subnet_group_name: subnet_group_id)
        rescue Aws::ElastiCache::Errors::CacheSubnetGroupNotFoundFault