code: func (dbInst *DB) Open() {
  	dbInst.mux.Lock()
  	defer dbInst.mux.Unlock()
  	if dbInst.dbState == opened {
  		return
  	}
  	dbOpts := &opt.Options{}
  	dbPath := dbInst.conf.DBPath
  	var err error
  	var dirEmpty bool
  	if dirEmpty, err = util.CreateDirIfMissing(dbPath); err != nil {
  		panic(fmt.Sprintf("Error creating dir if missing: %s", err))
  	}
  	dbOpts.ErrorIfMissing = !dirEmpty
  	if dbInst.db, err = leveldb.OpenFile(dbPath, dbOpts); err != nil {
  		panic(fmt.Sprintf("Error opening leveldb: %s", err))
  	}
  	dbInst.dbState = opened
  }
docs: // Open opens the underlying db