code: func (b *Uint) UnmarshalText(input []byte) error {
  	var u64 Uint64
  	err := u64.UnmarshalText(input)
  	if u64 > Uint64(^uint(0)) || err == ErrUint64Range {
  		return ErrUintRange
  	} else if err != nil {
  		return err
  	}
  	*b = Uint(u64)
  	return nil
  }
docs: // UnmarshalText implements encoding.TextUnmarshaler.