code: func StatusIsNot(statuses ...int) StacktracePred {
  	return func(status int) bool {
  		for _, s := range statuses {
  			if status == s {
  				return false
  			}
  		}
  		return true
  	}
  }
docs: // StatusIsNot returns a StacktracePred which will cause stacktraces to be logged
  // for any status *not* in the given list.