code: func Label(v Val) string {
  	if v == nil {
  		return "<nil>"
  	}
  	if s, ok := v.(fmt.Stringer); ok {
  		return s.String()
  	}
  	if b, ok := v.([]byte); ok {
  		return ToBin(b)
  	}
  	panic(fmt.Sprintf("unsupported value type %T", v))
  }
docs: // Label displays the node's key in binary format