switch v.(type) could eliminate type assertions in switch cases
	switch v := v.(type) {
	case int:
		m[k] = v * 2
	case string:
		m[k] = goStrings.Repeat(v, 2)
	default:
	}

最后发现居然在获取类型的时候会自动转掉,不得不说很贴心了 QAQ,果然码农最懂码农需要什么