presto-parser/src/main/java/io/prestosql/sql/tree/DefaultTraversalVisitor.java/DefaultTraversalVisitor/visitStartTransaction
class DefaultTraversalVisitor:    @Override
    protected R visitStartTransaction(StartTransaction node, C context)
    {
        for (TransactionMode transactionMode : node.getTransactionModes()) {
            process(transactionMode, context);
        }

        return null;
    }