title: Extend class in PHP
body: <p>I am trying to extend a class:</p>
  
  <pre><code>class CustomParsedown extends Parsedown {
      protected function blockComment($Line) { return; }
      protected function blockCommentContinue($Line, array $Block) { return; }
      protected function blockHeader($Line) { return; }
      protected function blockSetextHeader($Line, array $Block = NULL) { return; }
  }
  
  function markdown($markdown) {
      return CustomParsedown::instance()-&gt;setMarkupEscaped(true)-&gt;text($markdown);
  }
  </code></pre>
  
  <p>If I run <code>markdown()</code> with markdown from another page, the changes in the code do not go into effect. For example, I can still create a heading. Am I extending the class correctly?</p>