adjacent-elements">
                  <code class="decorated-title"><span class='decorator'>func</span><span class='decorator empty-token'> </span><span class='identifier'>mutate</span><span class='decorator'>&lt;</span><span class='decorator'>Result</span><span class='decorator'>&gt;((</span><span class='decorator'>inout</span><span class='decorator empty-token'> </span><span class='decorator'>Element</span><span class='decorator'>) -&gt; </span><span class='decorator'>Result</span><span class='decorator'>