code: func WriteDatabaseVersion(db ethdb.Writer, version uint64) {
  	enc, err := rlp.EncodeToBytes(version)
  	if err != nil {
  		log.Crit("Failed to encode database version", "err", err)
  	}
  	if err = db.Put(databaseVerisionKey, enc); err != nil {
  		log.Crit("Failed to store the database version", "err", err)
  	}
  }
docs: // WriteDatabaseVersion stores the version number of the database