title: Using a return keyword with no return value?
body: <p>I have been noticing in some PHP design patterns, some authors who write code examples, have  return inside the method but it doesn't specify return value .
   It just says "return"</p>
  
  <p>Can some one please explain me what is the purpose of doing that? Below is an example</p>
  
  <p>Thank you!</p>
  
  <pre><code>function addListItem(ListItem $listItem){
      if(in_array($listItem, $this-&gt;listitems, true)){
          return;
      }
      $this-&gt;listitems[] = $listItem;
  
  }
  </code></pre>