Hello,

I made commits r11209-11212 for making easier to change claims via API

you can see the manual here:
http://www.mediawiki.org/wiki/Manual:Pywikipediabot/Wikidata#Changing_or_creating_claims.2Fstatements

you simply can call and change properties and give them values

I tested it on two categories and it worked (http://www.wikidata.org/wiki/Wikidata:Requests_for_permissions/Bot/Dexbot_2)

I haven't work on errors yet (for example if new and old values are same the code returns error instead of simply not saving the change like mediawiki) but if there is any bugs, tell me

Cheers

--
Amir