presto-parser/src/main/java/io/prestosql/sql/parser/AstBuilder.java/AstBuilder/visitCreateRole
class AstBuilder:    @Override
    public Node visitCreateRole(SqlBaseParser.CreateRoleContext context)
    {
        return new CreateRole(
                getLocation(context),
                (Identifier) visit(context.name),
                getGrantorSpecificationIfPresent(context.grantor()));
    }