sp;key&nbsp;*&nbsp;<span class="keywordsign">'</span>a<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;max_binding&nbsp;:&nbsp;<span class="keywordsign">'</span>a&nbsp;t&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;key&nbsp;*&nbsp;<span class="keywordsign">'</span>a<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;choose&nbsp;:&nbsp;<span class="keywordsign">'</span>a&nbsp;t