his will shadow the official <a href="https://caml.inria.fr/pub/docs/manual-ocaml/libref/List.html#VALfind_map"><code>find_map</code></a> in 4.10</p></dd></dl><dl><dt class="spec value" id="val-filter_opt"><a href="#val-filter_opt" class="anchor"></a><code><span class="keyword">val</span> filter_opt : <span><span><span class="type-var">'a</span> option</span> <a href="index.html#type-t">t</a></span> <span>&#45;&gt;</span> <span><span class="type-var">'a</span> <a href="index.html#type-t">t</a></span></code>