title: Core Data Transformable attributes NOT working with NSPredicate
body: <p>I often use <code>Transformable</code> for <code>Core Data attributes</code>, so I can change them later.</p>
  
  <p>However, it seems like, if I want to use <code>NSPredicate</code> to find a <code>NSManagedObject</code>, using <code>"uniqueKey == %@"</code>, or <code>"uniqueKey MATCHES[cd] %@"</code>, it's not working as it should.</p>
  
  <p>It always misses matching objects, until I change the attributes of the uniqueKey of the matching object to have specific class like <code>NSString</code>, or <code>NSNumber</code>.</p>
  
  <p>Can someone explain the limitation of using <code>NSPredicate</code> with <code>Transformable</code> attributes?</p>