code: func printVal(l string, v interface{}) {
  	switch f := v.(type) {
  	case uint, uint64:
  		printFmt(l, "%d", f)
  	case string:
  		printFmt(l, "%s", f)
  	default:
  		printFmt(l, "%v", f)
  	}
  }
docs: // printVal prints the given value with the specified label.