code: func (db *DB) lDelete(t *batch, key []byte) int64 {
  	mk := db.lEncodeMetaKey(key)
  
  	var headSeq int32
  	var tailSeq int32
  	var err error
  
  	it := db.bucket.NewIterator()
  	defer it.Close()
  
  	headSeq, tailSeq, _, err = db.lGetMeta(it, mk)
  	if err != nil {
  		return 0
  	}
  
  	var num int64
  	startKey := db.lEncodeListKey(key, headSeq)
  	stopKey := db.lEncodeListKey(key, tailSeq)
  
  	rit := store.NewRangeIterator(it, &store.Range{
  		Min:  startKey,
  		Max:  stopKey,
  		Type: store.RangeClose})
  	for ; rit.Valid(); rit.Next() {
  		t.Delete(rit.RawKey())
  		num++
  	}
  
  	t.Delete(mk)
  
  	return num
  }
docs: //	ps : here just focus on deleting the list data,
  //		 any other likes expire is ignore.