// refer: https://github.com/golang/go/issues/64739typecountrystruct{string} typeCountrystruct{}
func(cCountry) Australia() country {...} func(cCountry) Canada() country {...}
func(cCountry) China() country {...}
func(cCountry) England() country {...}
func(cCountry) France() country {...}
func(cCountry) Germany() country {...}
func(cCountry) Japan() country {...}
func(cCountry) Mexico() country {...}
func(cCountry) Morocco() country {...}
func(cCountry) Zimbabwe() country {...}
// ...