code: def set_time(self, time):
          
          rest_time = int(self.song_total_time) - self.time - 1
          minute = int(rest_time) / 60
          sec = int(rest_time) % 60
  
          return str(minute).zfill(2) + ':' + str(sec).zfill(2)
docs: 时间状态