code: func (mvcc *MVCCLevelDB) BatchGet(ks [][]byte, startTS uint64, isoLevel kvrpcpb.IsolationLevel) []Pair {
  	mvcc.mu.RLock()
  	defer mvcc.mu.RUnlock()
  
  	pairs := make([]Pair, 0, len(ks))
  	for _, k := range ks {
  		v, err := mvcc.getValue(k, startTS, isoLevel)
  		if v == nil && err == nil {
  			continue
  		}
  		pairs = append(pairs, Pair{
  			Key:   k,
  			Value: v,
  			Err:   errors.Trace(err),
  		})
  	}
  	return pairs
  }
docs: // BatchGet implements the MVCCStore interface.