class Rufus::Scheduler::RepeatJob

def last_at=(last)
  @last_at =
    if last
      ldur = Rufus::Scheduler.parse_duration(last, no_error: true)
      (ldur && (EoTime.now + ldur)) || EoTime.make(last)
    else
      nil
    end
  fail ArgumentError.new(
    "cannot set last[_at|_in] in the past: " +
    "#{last.inspect} -> #{@last_at.inspect}"
  ) if last && @last_at < EoTime.now
  @last_at
end