title: Change value in a nested NSMutableDictionary
body: <p>I have a NSMutableDictionary to which I want to change the value of an element.</p>
  
  <pre><code>//My dictionary:
  
  {
      objectId = 8ED998yWd1;
      cardInfo =     {
          state = published; //THIS!
          price = 40;
          color = red;
          }   
  };
  </code></pre>
  
  <p>I have tried several ways, but the value does not change, like this:</p>
  
  <pre><code>[dictionary setObject:@"reserved" forKey:@"state"]; //nope
  </code></pre>
  
  <p>or this:</p>
  
  <pre><code>[dictionary setValue:@"reserved" forKeyPath:@"cardInfo.state"]; //nope
  </code></pre>
  
  <p>or that:</p>
  
  <pre><code>[[dictionary objectForKey:@"cardInfo"] setObject:@"reserved" forKey:@"state"]; //no
  </code></pre>
  
  <p>and this:</p>
  
  <pre><code>[dictionary setObject:@"reserved" forKey:[[dictionary objectForKey:@"cardInfo"] objectForKey:@"state"]];
  </code></pre>
  
  <p>How can I change the object "state" from "published" to "reserved"?</p>
  
  <p>Thank you!</p>