</span><span class="pn">,</span> <span class="n">1</span><span class="pn">,</span> <span class="n">1</span><span class="pn">)</span> <span class="pn">|]</span><span class="pn">,</span> <span class="id">Leaf</span> <span class="id">LeftTo</span><span class="pn">,</span> <span onmouseout="hideTip(event, 'fs2', 2)" onmouseover="showTip(event, 'fs2', 2)" class="id">Option</span><span class="pn">.</span><span onmouseout="hideTip(event, 'fs3', 3)" onmouseover="showTip(event, 'fs3', 3)" class="id">None</span><span