code: func GetClientArchType(o dhcp6.Options) (ArchTypes, error) {
  	v, err := o.GetOne(dhcp6.OptionClientArchType)
  	if err != nil {
  		return nil, err
  	}
  
  	var a ArchTypes
  	err = a.UnmarshalBinary(v)
  	return a, err
  }
docs: // GetClientArchType returns the Client System Architecture Type Option value,
  // described in RFC 5970, Section 3.3.
  //
  // The ArchTypes slice returned contains a list of one or more ArchType values.
  // The first ArchType listed is the client's most preferable value.