code: def issue_instant_ok(self):
          
          upper = time_util.shift_time(time_util.time_in_a_while(days=1),
                                       self.timeslack).timetuple()
          lower = time_util.shift_time(time_util.time_a_while_ago(days=1),
                                       -self.timeslack).timetuple()
          # print("issue_instant: %s" % self.response.issue_instant)
          # print("%s < x < %s" % (lower, upper))
          issued_at = str_to_time(self.response.issue_instant)
          return lower < issued_at < upper
docs: Check that the response was issued at a reasonable time