> { indexing: attribute }\n" +                         "  }\n" +                         "}";         String adSdContent =                 "search ad {\n" +                         "  document ad {\n" +                         "    field campaign_ref type reference<campaign> { indexing: attribute }\n" +                         "  }\n" +                         "}";         builder.importString(campaignSdContent);         builder.importString(adSdContent);         