Parliamentarian Endpoint doesn't return faction
https://api.votelog.ch/api/v1/parliamentarian?ps=300&os=0&lp=51&lang=de&fields=FirstName&fields=LastName&fields=Party&fields=Faction
returns 400
https://api.votelog.ch/api/v1/parliamentarian?ps=300&os=0&lp=51&lang=de&fields=FirstName&fields=LastName&fields=Party&fields=Faction
returns 400