title: NSString Category Method Not Getting Called
body: <p>The problem I am trying to solve is to convert nil strings into empty strings so I can put that as a value in <code>NSDictionary</code>. </p>
  
  <p>I have the following code: </p>
  
  <pre><code>//Accessed in class  
  prospect.title = [self.titleLabel.text emptyWhenNil];
  
  // NSString+Additions Category
  
  -(NSString *) emptyWhenNil
  {
     if(self == nil)
        return @"";
  
     return self;
   }
  </code></pre>
  
  <p>But for some reason the <code>emptyWhenNil</code> method is never even invoked!! I am lost..</p>