pan> <span class="kt">String</span><span class="p">?</span> <span class="o">=</span> <span class="kc">nil</span><span class="p">,</span>
    
    <span class="nv">configure</span> <span class="p">:</span> <span class="p">(</span><span class="k">inout</span> <span class="k">Self</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="p">()</span> <span class="o">=</span> <span class="p">{</span> <span class="n">_</span> <span class="k">in</span> <span class="p">}</span>
<span class="p">)</sp