rrow">&#45;&gt;</span></span> <span>string <span class="arrow">&#45;&gt;</span></span> <span>string <span class="arrow">&#45;&gt;</span></span> string</span></code></div></div><div class="odoc-spec"><div class="spec value anchored" id="val-create_arg_type"><a href="#val-create_arg_type" class="anchor"></a><code><span><span class="keyword">val</span> create_arg_type : 
  <span><span class="optlabel">?key</span>:<span><span class="type-var">'a</span> <span class="xref-unresolved">Core</span>.Univ_map.Multi.Ke