span> <span class="function-name">callback_fn</span>(proxy, context, success, failure)
  <span class="keyword">if</span> failure ~= <span class="keyword">nil</span> <span class="keyword">then</span>  <span class="comment">-- error from the DBus Method
</span>    <span class="global">print</span>(<span class="string">"Error:"</span>, failure)
    <span class="global">print</span>(<span class="string">"Error code:"</span>, failure.code)
    <span class="comment">-- add the data from the DBus method to the con