ass="label label-primary">string</span></td>
                  <td><code>success</code></td>
                  <td>The class that will be applied to the bar when a promise is resolved (completed successfully).</td>
                </tr>
                <tr>
                  <td><code>error_class</code></td>
                  <td><span class="label label-primary">string</span></td>
                  <td><code>error</code></td>
                  <td>The class that will be applied to the bar when a promise is