code: func atois(strs []string) ([]int, error) {
  	var a []int
  	for _, str := range strs {
  		i, err := strconv.Atoi(str)
  		if err != nil {
  			return nil, err
  		}
  		a = append(a, i)
  	}
  	return a, nil
  }
docs: // atois parses a slice of strings into integers.