proc getMinIter(expr: Expr; field: Field; dt: DateTime): Option[int] {.
    ...raises: [], tags: [], forbids: [].}

proc getNext(cron: Cron; dt: DateTime): Option[DateTime] {.
    ...raises: [KeyError, Exception], tags: [RootEffect], forbids: [].}

proc getNext(expr: Expr; field: Field; dt: DateTime): Option[int] {.
    ...raises: [Exception], tags: [RootEffect], forbids: [].}

proc getNext(field: Field; dt: DateTime): Option[int] {....raises: [Exception],
    tags: [RootEffect], forbids: [].}

proc getNextForAll(expr: Expr; field: Field; dt: DateTime): Option[int] {.
    ...raises: [], tags: [], forbids: [].}

proc getNextForIndex(expr: Expr; field: Field; dt: DateTime): Option[int] {.
    ...raises: [], tags: [], forbids: [].}

proc getNextForLastDayOfMonth(expr: Expr; field: Field; dt: DateTime): Option[
    int] {....raises: [], tags: [], forbids: [].}

proc getNextForLastDayOfWeek(expr: Expr; field: Field; dt: DateTime): Option[int] {.
    ...raises: [], tags: [], forbids: [].}

proc getNextForNum(expr: Expr; field: Field; dt: DateTime): Option[int] {.
    ...raises: [], tags: [], forbids: [].}

proc getNextForRange(expr: Expr; field: Field; dt: DateTime): Option[int] {.
    ...raises: [], tags: [], forbids: [].}

proc getNextForSeq(expr: Expr; field: Field; dt: DateTime): Option[int] {.
    ...raises: [Exception], tags: [RootEffect], forbids: [].}

proc getNextForStepAll(expr: Expr; field: Field; dt: DateTime): Option[int] {.
    ...raises: [], tags: [], forbids: [].}

proc getNextForStepNum(expr: Expr; field: Field; dt: DateTime): Option[int] {.
    ...raises: [], tags: [], forbids: [].}

proc getNextForStepRange(expr: Expr; field: Field; dt: DateTime): Option[int] {.
    ...raises: [], tags: [], forbids: [].}

proc newCron(second: string = "*"; minute: string = "*"; hour: string = "*";
             day_of_month: string = "*"; day_of_week: string = "*";
             month: string = "*"; year: string = "*"): Cron {.
    ...raises: [ValueError, Exception], tags: [RootEffect], forbids: [].}