title: Creating a custom method with completion block
body: <blockquote>
    <p><strong>Possible Duplicate:</strong><br>
    <a href="https://stackoverflow.com/questions/7180552/implementing-a-method-taking-a-block-to-use-as-callback">Implementing a method taking a block to use as callback</a>  </p>
  </blockquote>
  
  
  
  <p>I couldn't find any clear explanation about how to implement a method that executes a completion block.</p>
  
  <p>I know that NSOperation can be subclasses and used with calling <code>setCompletionBlock:</code> . Anyone knows if this is possible just by implementing in the m. file?</p>