返回時間。時間零值當函式有錯誤時

const timeFormat = "15 Monday January 2006"

func ParseDate(s string) (time.Time, error) {
    t, err := time.Parse(timeFormat, s)
    if err != nil {
        // time.Time{} returns January 1, year 1, 00:00:00.000000000 UTC
        // which according to the source code is the zero value for time.Time
        // https://golang.org/src/time/time.go#L23
        return time.Time{}, err
    }
    return t, nil
}