title: Using classes without namespace with Yii2
body: <p>I want to use <a href="https://github.com/2Checkout/2checkout-php" rel="noreferrer">Checkout SDK</a> with Yii2 but since this library does not support PSR-4 standards (namespaces) I am having trouble to integrate it. How can I use this library for my purpose? </p>
  
  <p><strong>EDIT</strong></p>
  
  <p>As suggested I tried to use class as        </p>
  
  <pre><code>$sale = new \Twocheckout_Sale();
  </code></pre>
  
  <p>but still I am unable to make it work.</p>