type_declaration&nbsp;=&nbsp;{<br>
&nbsp;&nbsp;&nbsp;&nbsp;ptype_name&nbsp;:&nbsp;string&nbsp;<span class="constructor">Asttypes</span>.loc;<br>
&nbsp;&nbsp;&nbsp;&nbsp;ptype_params&nbsp;:&nbsp;(<span class="constructor">Parsetree</span>.core_type&nbsp;*&nbsp;<span class="constructor">Asttypes</span>.variance)&nbsp;list;<br>
&nbsp;&nbsp;&nbsp;&nbsp;ptype_cstrs&nbsp;:<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(<span class="constructor">Parsetree</span>.core_type&nbsp;*&nbsp;<span class="constructor">Parsetree<