def Default() -> 'Blockchain':
        """
        Get the default registered blockchain instance.

        Returns:
            obj: Currently set to `neo.Implementations.Blockchains.LevelDB.LevelDBBlockchain`.
        """
        if Blockchain._instance is None:
            Blockchain._instance = Blockchain()
            Blockchain.GenesisBlock().RebuildMerkleRoot()

        return Blockchain._instance
Get the default registered blockchain instance.

        Returns:
            obj: Currently set to `neo.Implementations.Blockchains.LevelDB.LevelDBBlockchain`.