title: Wordpress add filter to the_content()
body: <p>I'm trying to add a code to <code>the_content()</code> function. I tried the following</p>
  
  <pre><code>function add_something($content) {
      echo "test";
  }
  add_filter( 'the_content', 'add_something', 6); 
  </code></pre>
  
  <p>After adding the filter my posts return just the echo <code>test</code> without the content. How can I execute my custom code without omitting the content?</p>