>T</a><span class="token operator">?</span><span class="token punctuation">)</span><span class="token operator"> -&gt; </span><a href="../-entity/lookup-in-read-values.html">R</a><span class="token operator">?</span><span class="token punctuation">, </span></span><span class="parameter ">notFound<span class="token operator">: </span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token operator"> -&gt; </span><a href="../-entity/lookup-in-read-values.html">R</a><