p;&nbsp;&nbsp;<span class="keyword">sig</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">type</span>&nbsp;elt<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">and</span>&nbsp;t<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;empty&nbsp;:&nbsp;<span class="constructor">MoreLabels</span>.<span class="constructor">Set</span>.<span class="constructor">S</span>.t<br>
&nbsp;&nbsp;