我正在尝试将我的NSManagedObject转换成一个字典，这样我就可以将它序列化为JSON。funcfetchRecord()->[Record]{letfetchRequest=NSFetchRequest(entityName:"Record")letcontext=PersistenceService.contextfetchRequest.resultType=.dictionaryResultTypedo{records=trycontext.fetch(Record.fetchRequest())}catch{print("ErrorfetchingdatafromCo