See example at https://www.wikidata.org/wiki/Wikidata:WikiProject_Video_games/Statistics/Country_of_origin
The groupings query is https://w.wiki/wVm and returns items such as https://www.wikidata.org/wiki/Q61976205 which have `P495`=`Unknown value`
Triggering an update results with
```<class 'pywikibot.exceptions.InvalidTitle'> 'T2157987814' is not a valid item page title```
```
web_1 | self.process_page(page)
web_1 | File "/code/integraality/pages_processor.py", line 116, in process_page
web_1 | output = stats.retrieve_and_process_data()
web_1 | File "/code/integraality/property_statistics.py", line 614, in retrieve_and_process_data
web_1 | text += self.make_stats_for_one_grouping(grouping, item_count, higher_grouping)
web_1 | File "/code/integraality/property_statistics.py", line 543, in make_stats_for_one_grouping
web_1 | group_item = pywikibot.ItemPage(self.repo, grouping)
web_1 | File "/usr/local/lib/python3.7/site-packages/pywikibot/page/__init__.py", line 4694, in __init__
web_1 | super(ItemPage, self).__init__(site, title, ns=ns)
web_1 | File "/usr/local/lib/python3.7/site-packages/pywikibot/page/__init__.py", line 4392, in __init__
web_1 | self._link.title)
web_1 | File "/usr/local/lib/python3.7/site-packages/pywikibot/page/__init__.py", line 4095, in __init__
web_1 | % (self.id, self.entity_type))
web_1 | pywikibot.exceptions.InvalidTitle: 'T2157920837' is not a valid item page title
```