code: def sync(self, *sids):
          
          if sids == ():
              sids = [sid for (sid,) in self.dbcur.execute(SQL_SENSOR_ALL)]
          for sid in sids:
              self.dbcur.execute(SQL_TMPO_LAST, (sid,))
              last = self.dbcur.fetchone()
              if last:
                  rid, lvl, bid, ext = last
                  self._clean(sid, rid, lvl, bid)
                  # prevent needless polling
                  if time.time() < bid + 256:
                      return
              else:
                  rid, lvl, bid = 0, 0, 0
              self._req_sync(sid, rid, lvl, bid)
docs: Synchronise data
  
          Parameters
          ----------
          sids : list of str
              SensorIDs to sync
              Optional, leave empty to sync everything