    <h4>Return Value</h4>
                        <p>A new <code>NSError</code> instance with the Matisse error domain and the unknown error code.</p>
                      </div>
                    </section>
                  </div>
                </li>
                <li class="item">
                  <div>
                    <code>
                    <a name="/s:So7NSErrorC7MatisseE20matisseDownloadErroryABSSSgFZ"></a>
                    <a name="//apple_ref/swift/Method/matisseDownloadError(_:)"