title: Rendering a collection of partials when the given collection is nil
body: <p>Given the following example from the Rails documentation:</p>
  
  <pre><code>&lt;%= render(partial: "ad", collection: @advertisements) || "There's no ad to be displayed" %&gt;
  </code></pre>
  
  <p>My question is how to wrap the </p>
  
  <blockquote>
    <p>"There's no ad to be displayed"</p>
  </blockquote>
  
  <p>string into html tag in order to add css classes to it.</p>
  
  <p>For example,</p>
  
  <pre><code>&lt;span class='text-muted'&gt;There's no ad to be displayed&lt;/span&gt;
  </code></pre>