def clean_aged(time_now)
      near_past = time_now - @time_window_in_seconds
      @errors = @errors.reverse.select{|time_stamp| time_stamp  > near_past }.reverse.to_a
    end
def clean_aged(time_now)
      near_past = time_now - @time_window_in_seconds
      @errors = @errors.reverse.select{|time_stamp| time_stamp  > near_past }.reverse.to_a
    end
clean up errors that are older than time_window_in_secons