let searchDescriptor=NSSortDescriptor(key: "part.typeANDVariant.actVariantName", ascending:true)

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'keypath part.typeANDVariant.actVariantName not found in entity <NSSQLEntity Component id=7>'

let searchDescriptor=NSSortDescriptor(key: "part.partDescription", ascending:true)