title: I'm getting from the database dictionary in which there is one or more objects NSNull
body: <p>I'm getting from the database dictionary in which there is one or more objects <code>NSNull</code>. In the future, I can not in any way to work with him as the app crash. I tried many ways to remove from the dictionary <code>NSNull</code> objects, method <code>removeObjectForKey</code> but any attempt to do this I get an error that is an array of reason: </p>
  
  <pre><code>- [__ NSArrayM removeObjectForKey:]: unrecognized selector sent to an instance
  </code></pre>
  
  <p>And I can not remove these objects by method the array <code>removeObjectAtIndex</code> as this dictionary. I only thought of how to do this is to remove these objects by type. Is it possible to do so, remove the object from the dictionary that match <code>NSNull</code> type? Or maybe there is another solution to this problem?</p>
  
  <p>Thank you for any help!</p>