# File lib/ice_cube/schedule.rb, line 243
    def occurring_at?(time)
      time = TimeUtil.match_zone(time, start_time) or raise ArgumentError, "Time required, got #{time.inspect}"
      if duration > 0
        return false if exception_time?(time)
        occurs_between?(time - duration + 1, time)
      else
        occurs_at?(time)
      end
    end