code: def _watchdog(self):
          
          sid = self._playingsong['sid']
          while 1:
  
              # 本次播放里去重
              while 1:
                  song = douban.get_song(sid)
                  if not song:
                      continue
                  sid = song['sid']
                  if sid not in self.hash_sid:
                      break
  
              self._playlist.put(song)
              if not self._playingsong:
                  self._playlist.get(False)
docs: 更新队列线程