keyword">type</span>&nbsp;usage_msg&nbsp;=&nbsp;string
&nbsp;&nbsp;<span class="keyword">type</span>&nbsp;anon_fun&nbsp;=&nbsp;string&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;unit
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;parse&nbsp;:
&nbsp;&nbsp;&nbsp;&nbsp;(<span class="constructor">Arg</span>.key&nbsp;*&nbsp;<span class="constructor">Arg</span>.spec&nbsp;*&nbsp;<span class="constructor">Arg</span>.doc)&nbsp;list&nbsp;<span class="keywordsign">-&gt;</span>
&nbsp;&nbsp;&nbsp;&nbsp;<span cla