SwiftImport.swift

public class SwiftImport<Element:NSManagedObject> {
   public class func importObject(context:NSManagedObjectContext)
          -> (dict:JSONDictionary) throws -> Element {
        // TODO
   }
}

// Which will look like this in caller

let data:NSData = .. // some data probably from responce
if let json:AnyObject? = try? NSJSONSerialization.JSONObjectWithData(data, options: []) } {
   let users = try? SwiftImport<User>.importObject(context:context)(dict:jsonDict)
   
   ...
}