step7 returnの書き方のリファクタ

roman.go

package roman

type Arabian uint16

func (in Arabian) ToRoman() (out string) {
	numbers := []struct {
		arabian Arabian
		roman   string
	}{
		{5, "V"},
		{1, "I"},
	}
	for remain := in; remain != 0; {
		for _, n := range numbers {
			if remain >= n.arabian {
				out += n.roman
				remain = remain - n.arabian
			}
		}
	}
	return
}