 class="declaration">
                <div class="language">
                  <pre class="highlight swift"><code><span class="kd">open</span> <span class="kd">class</span> <span class="kt">LayoutPlaceholder</span><span class="o">&lt;</span><span class="kt">Element</span><span class="p">,</span> <span class="kt">Super</span><span class="o">&gt;</span> <span class="p">:</span> <span class="kt">LayoutGuide</span><span class="o">&lt;</span><span class="kt">Super</span><span class="o">&gt;</span> <span class="k