Oh, wait. Actually, this will return an error even if the env. var. is not set. So careful here, it could turn into a regression. If the env. var. is not set, we should return a default, otherwise, log an error + the default return.  ```go  vv, ok := os.LookupEnv(key)  if !ok {      return def  }  v, err := strconv.Atoi(vv)  // ...  ```