fix groupby to use set - get just one committee of each type
fix groupby to use set - get just one committee of each type

alonisser/Open-Knesset,OriHoch/Open-Knesset,alonisser/Open-Knesset,alonisser/Open-Knesset,MeirKriheli/Open-Knesset,OriHoch/Open-Knesset,OriHoch/Open-Knesset,MeirKriheli/Open-Knesset,daonb/Open-Knesset,daonb/Open-Knesset,MeirKriheli/Open-Knesset,alonisser/Open-Knesset,daonb/Open-Knesset,OriHoch/Open-Knesset,MeirKriheli/Open-Knesset,daonb/Open-Knesset