method Temporal.PlainYearMonth.prototype.sincesince(other: Temporal.PlainYearMonth | PlainYearMonthLike | string, options?: DifferenceOptions<"year" | "month">): Temporal.DurationParametersother: Temporal.PlainYearMonth | PlainYearMonthLike | stringoptionaloptions: DifferenceOptions<"year" | "month">ReturnsTemporal.Duration