ordsign">-&gt;</span>&nbsp;<span class="keywordsign">'</span>a<br>
&nbsp;&nbsp;<span class="keyword">exception</span>&nbsp;<span class="constructor">Internal_error</span>&nbsp;<span class="keyword">of</span>&nbsp;string<br>
&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;internal_error&nbsp;:&nbsp;(<span class="keywordsign">'</span>a,&nbsp;unit,&nbsp;string,&nbsp;<span class="keywordsign">'</span>b)&nbsp;<span class="constructor">Pervasives</span>.format4&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<