FromUnix convert unix timestamp to time.Time.

MustParseAliTime parses alipay time format, and falls back to now if parse failed.

MustParseWxTime parses wechat pay time format, and falls back to now if parse failed.

NewYearMonthDay creates a new instance for an enum.Cycle.

NewYearMonthDayN creates a new instance for n enum.Cycle.

ParseAliTime parses alipay time string.

ParseWxTime is used to parse wxpay's time format.

PickEarlier selects a time that comes earlier from two.

PickLater select from two moments the one that comes later.

YearMonthDay is the unit of a enum.Cycle.