ow">&#45;&gt;</span></span> <span><span class="label">f</span>:<span>(<span><span><span class="type-var">'a</span> option</span> <span class="arrow">&#45;&gt;</span></span> <span><span class="type-var">'a</span> option</span>)</span> <span class="arrow">&#45;&gt;</span></span> unit</span></code></div></div><div class="odoc-spec"><div class="spec value anchored" id="val-find_exn"><a href="#val-find_exn" class="anchor"></a><code><span><span class="keyword">val</span> find_exn : <span><span><span class="type-v