presto-parser/src/main/java/io/prestosql/sql/parser/AstBuilder.java/AstBuilder/visitUnnest
class AstBuilder:    @Override
    public Node visitUnnest(SqlBaseParser.UnnestContext context)
    {
        return new Unnest(getLocation(context), visit(context.expression(), Expression.class), context.ORDINALITY() != null);
    }