'Check that the request was issued at a reasonable time'

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()
    issued_at = time_util.str_to_time(self.message.issue_instant)
    return ((issued_at > lower) and (issued_at < upper))
