code: func indexesOutsideRange(start time.Time, end time.Time, results []time.Time) []int {
  	if start.After(end) {
  		panic("start date is after end date")
  	}
  	indexes := make([]int, 0, len(results))
  	for i, result := range results {
  		if result.Equal(end) || result.After(end) {
  			indexes = append(indexes, i)
  		}
  		if result.Before(start) {
  			indexes = append(indexes, i)
  		}
  	}
  	return indexes
  }
docs: // indexesOutsideRange returns the indexes of times in results that are outside
  // of [start, end). indexesOutsideRange panics if start is later than end.