func getFetchRequest(entityName: String) -> NSFetchRequest<NSFetchRequestResult> {
        let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: entityName)
        return fetchRequest
}

func getCoreDataModels<T>(entityName: String) -> [T]? {
        do {
            let fetchRequest = self.getFetchRequest(entityName: entityName)
            let results = try self.dataManager.managedObjectContext.fetch(fetchRequest) as? [T]
            return results
        } catch {
            return nil
        }
}