TimedCache[K] = object of RootObj
  head, tail: TimedEntry[K]
  entries: Table[K, TimedEntry[K]]
  timeout: Duration

TimedEntry[K] = ref object of RootObj
  key: K
  addedAt: Moment
  expiresAt: Moment
  next, prev: TimedEntry[K]

Timeout = (value: 10000000000)

func addedAt[K](t: TimedCache[K]; k: K): Moment {....raises: [].}

func contains[K](t: TimedCache[K]; k: K): bool {....raises: [].}

func del[K](t: var TimedCache[K]; key: K): Opt[TimedEntry[K]] {....raises: [].}

func expire(t: var TimedCache; now: Moment = Moment.now()) {....raises: [].}

func init[K](T: type TimedCache[K]; timeout: Duration = Timeout): T:type {.
    ...raises: [].}

func put[K](t: var TimedCache[K]; k: K; now = Moment.now()): bool {....raises: [].}