presto-parser/src/main/java/io/prestosql/sql/parser/AstBuilder.java/AstBuilder/visitTransactionAccessMode
class AstBuilder:    @Override
    public Node visitTransactionAccessMode(SqlBaseParser.TransactionAccessModeContext context)
    {
        return new TransactionAccessMode(getLocation(context), context.accessMode.getType() == SqlBaseLexer.ONLY);
    }