code: func GetIP(code dhcp4.OptionCode, o dhcp4.Options) IP {
  	v := o.Get(code)
  	if v == nil {
  		return nil
  	}
  	var ip IP
  	if err := (&ip).UnmarshalBinary(v); err != nil {
  		return nil
  	}
  	return ip
  }
docs: // GetIP returns the IP encoded in `code` option of `o`, if there is one.