Clean up the backend csv class and add typehints
Clean up the backend csv class and add typehints

sumocoders/forkcms,bartdc/forkcms,sumocoders/forkcms,justcarakas/forkcms,carakas/forkcms,carakas/forkcms,DegradationOfMankind/forkcms,sumocoders/forkcms,mathiashelin/forkcms,jessedobbelaere/forkcms,jonasdekeukelaere/forkcms,carakas/forkcms,sumocoders/forkcms,sumocoders/forkcms,riadvice/forkcms,jeroendesloovere/forkcms,justcarakas/forkcms,bartdc/forkcms,jacob-v-dam/forkcms,jessedobbelaere/forkcms,tommyvdv/forkcms,jacob-v-dam/forkcms,tommyvdv/forkcms,jacob-v-dam/forkcms,forkcms/forkcms,Katrienvh/forkcms,tommyvdv/forkcms,tommyvdv/forkcms,mathiashelin/forkcms,Katrienvh/forkcms,jonasdekeukelaere/forkcms,jeroendesloovere/forkcms,jonasdekeukelaere/forkcms,riadvice/forkcms,jonasdekeukelaere/forkcms,carakas/forkcms,jessedobbelaere/forkcms,forkcms/forkcms,jacob-v-dam/forkcms,jeroendesloovere/forkcms,mathiashelin/forkcms,DegradationOfMankind/forkcms,mathiashelin/forkcms,DegradationOfMankind/forkcms,riadvice/forkcms,justcarakas/forkcms,riadvice/forkcms,jeroendesloovere/forkcms,DegradationOfMankind/forkcms,Katrienvh/forkcms,forkcms/forkcms,jessedobbelaere/forkcms,Katrienvh/forkcms,bartdc/forkcms,forkcms/forkcms,jonasdekeukelaere/forkcms,carakas/forkcms