an>&nbsp;<span class="constructor">OpamJson</span>.t<br>
&nbsp;&nbsp;<span class="keyword">module</span>&nbsp;<span class="constructor">Set</span>&nbsp;:<br>
&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">sig</span><br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">type</span>&nbsp;elt&nbsp;=&nbsp;t<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">type</span>&nbsp;t<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;empty&nbsp;:&nbsp;t<br>
&nbsp;&nbsp;&nbsp