an> <span class="n">dataOrNil</span><span class="p">,</span> <span class="n">errorOrNil</span><span class="p">)</span> <span class="k">in</span>

    <span class="k">guard</span> <span class="k">let</span> <span class="nv">vehicle</span> <span class="o">=</span> <span class="n">dataOrNil</span><span class="p">?</span><span class="o">.</span><span class="n">vehicles</span><span class="o">.</span><span class="n">first</span> <span class="nf">else</span> <span class="p">{</span> <span class="k">return</span> <