<s>[INST] We have a (simplistic) voting system with voters located in different districts. Voter data is the key with first name, last name and district as the values. 
We then have a relation where there are controversial issues (that is the official term!). We capture this data with the voter data as the key, plus another field that describes the issue. 
We record votes as follows: each candidate may appeal to any voter one time (for one issue). Any subsequent appeals for the same issue by the same candidate would be void.
The appeal is declared by passing the voter’s key, the candidate's key, and the controversy issue. 

So the key is tuple of (voter’s key, candidate’s key, controversy issue).
The appeal is only considered valid when the candidate is from the same district as the voter.
What is the best way to evaluate the behavior of each candidate from this data?[/INST]