title: unrecognized selector sent to instance when trying to retrieve string value
body: <p>I have a NSMutablearray wich contain NSArrays(each array contain int and String values).
  When i try to retrieve and display the data from the first array:
  That was ok with the int value, it was displayed correctly.</p>
  
  <pre><code>    NSLog(@"%i",[[[lesQuestions objectAtIndex:0] objectAtIndex:0] intValue]);
  </code></pre>
  
  <p>But when i try to display the String value:</p>
  
  <pre><code>    NSLog(@"%@",[[[lesQuestions objectAtIndex:0] objectAtIndex:1] stringValue]);
  </code></pre>
  
  <p>I got exception:</p>
  
  <pre><code>Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFString stringValue]: unrecognized selector sent to instance
  </code></pre>
  
  <p>I am definitely sure that the int value is the first item (index 0) and the String value is the second (index 1).
  When i log the MutableArray which holds the NSArrays, i got the values correctly, so the problem is on the reference of the item i guess. </p>