presto-parser/src/main/java/io/prestosql/sql/parser/AstBuilder.java/AstBuilder/visitPrepare
class AstBuilder:    @Override
    public Node visitPrepare(SqlBaseParser.PrepareContext context)
    {
        return new Prepare(
                getLocation(context),
                (Identifier) visit(context.identifier()),
                (Statement) visit(context.statement()));
    }