https://learn.microsoft.com/en-us/dotnet/api/system.collections.objectmodel.collection-1.setitem?view=netframework-4.8.1
CollectionT.SetItem(Int32, T) Method (System.Collections.ObjectModel) | Microsoft Learn
Replaces the element at the specified index.
methodsystemcollectionsmicrosoftlearn
https://lists.wikimedia.org/hyperkitty/list/pywikipedia-bugs@lists.wikimedia.org/thread/UUOYIKRPDTOG7B2NBYYAGGTY6P5HLVDS/
[ pywikipediabot-Bugs-3605830 ] setitem for wikidata doesn't work! - Pywikipedia-bugs -...
bugswikidatawork