pan class="keywordsign">'</span>a&nbsp;<span class="constructor">Bopt</span>.t<br>
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;wrap&nbsp;:&nbsp;?handler:(exn&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;bool)&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;(<span class="keywordsign">'</span>a&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="keywordsign">'</span>b)&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="keywordsign">'</span>a&nbsp;<span class="keywordsign">-&gt;