When some item have P12=Q1234, claimit.py does not change this value
when using -exists:ptq, script will add new value, but also can create duplicate statement with same value
https://www.wikidata.org/w/index.php?title=Q11723060&diff=141220723&oldid=87098576
See Also:
T72702: claimit and harvest_template - add another value for one property
T57002: claimit.py sample: add option to allow checking for identical statement (same property with same value)