Compare
https://tools.wmflabs.org/heritage/api/api.php?action=search&limit=1&format=html&srcountry=ru&props=name|municipality|address
to
https://tools.wmflabs.org/heritage/api/api.php?action=search&limit=1&format=html&srcountry=ru&props=name
In the second case, we get the following stacktrace:
```
Notice: Undefined property: stdClass::$municipality in includes/FormatHtml.php on line 41
Call Stack: 0.0073 666464
1. {main}() api.php:0 0.0920 1646552
2. ApiMain::dispatch() api.php:36 0.1042 1955648
3. ApiMonuments->executeModule() includes/ApiMain.php:39 0.1269 2190088
4. ApiMonuments->search() includes/ApiMonuments.php:72 0.9110 2388968
5. FormatBase->output() includes/ApiMonuments.php:338 0.9900 3876616
6. FormatHtml->outputContinue() includes/FormatBase.php:42
Notice: Undefined property: stdClass::$address in includes/FormatHtml.php on line 41
Call Stack: 0.0073 666464
1. {main}() api.php:0 0.0920 1646552
2. ApiMain::dispatch() api.php:36 0.1042 1955648
3. ApiMonuments->executeModule() includes/ApiMain.php:39 0.1269 2190088
4. ApiMonuments->search() includes/ApiMonuments.php:72 0.9110 2388968
5. FormatBase->output() includes/ApiMonuments.php:338 0.9900 3876616
6. FormatHtml->outputContinue() includes/FormatBase.php:42
```