title: Add another selector/name pair to an existing observer in NSNotificationCenter
body: <p>I'm not sure the exact reason for it (other than the ambiguity described below), but I've read that multiple observers shouldn't be added to the NSNotificationCenter for the same object. However, I would like to add a second selector/name pair to the same object in the notification center.</p>
  
  <p>I added the first one as follows:</p>
  
  <pre><code>[[NSNotificationCenter defaultCenter] addObserver:self
                                           selector:@selector(method1:) 
                                               name:@"method1Notification"
                                             object:nil];
  </code></pre>
  
  <hr />
  
  <h3>Option 1:</h3>
  
  <p>To add the second <strong>(like below)</strong> would seem to add "<code>self</code>" to the notification center again.</p>
  
  <pre><code>[[NSNotificationCenter defaultCenter] addObserver:self
                                           selector:@selector(method2:) 
                                               name:@"method2Notification"
                                             object:nil];
  </code></pre>
  
  <p>Is this okay? Or, if necessary, is there a way to simply add another selector/name pair to the "<code>self</code>" entry in the default notification center?</p>
  
  <hr />
  
  <h3>Option 2: (Pseudocode)</h3>
  
  <pre><code>[[[NSNotificationCenter defaultCenter] mySelfObserver]
                          addSelector:@selector(method2:) 
                                 name:@"method2Notification"
                               object:nil];
  </code></pre>
  
  <hr />
  
  <h3>Ambiguity:</h3>
  
  <p>It would seem that either way, if it were added a second time, in <code>dealloc:</code> it might need to be removed as an observer twice?</p>
  
  <pre><code>[[NSNotificationCenter defaultCenter] removeObserver:self];
  // ... REMOVE IT AGAIN IF OBSERVER ADDED TWICE TO NOTIFICATION CENTER?
  </code></pre>