code: func tostring(i interface{}) string {
  	var r string
  	switch x := i.(type) {
  	case string:
  		r = x
  	case uint64:
  		r = strconv.FormatUint(x, 10)
  	case int64:
  		r = strconv.FormatInt(x, 10)
  	case uint:
  		r = strconv.FormatUint(uint64(x), 10)
  	case int:
  		r = strconv.FormatInt(int64(x), 10)
  	default:
  		log.Panicf("Could not convert %v %t", x, x)
  	}
  	return r
  }
docs: // utility function to return only strings