title: How to check payment method on a WooCommerce order by id?
body: <p>I want to make some changes if the chosen payment method is COD. On existing WC_Order i have used</p>
  
  <pre><code>($order-&gt;payment_method_title == 'Cash On Delivery' ? ... : ... );
  </code></pre>
  
  <p>to retrieve the title.
  But i would like to check against the id (cod) because the title string gets translated to different languages which doesn't make it a good solution.</p>
  
  <p>Is there a way to retrieve the id on a WC_Order in woocommerce?</p>