n> )</span> <a href="../index.html#type-t">t</a></span> <span class="arrow">&#45;&gt;</span></span> <span><span>( <span><span class="type-var">'ok</span> <span class="arrow">&#45;&gt;</span></span> <span><span>( <span class="type-var">'okk</span>, <span class="type-var">'err</span> )</span> <a href="../index.html#type-t">t</a></span> )</span> <span class="arrow">&#45;&gt;</span></span> <span><span>( <span class="type-var">'okk</span>, <span class="type-var">'err</span> )</span> <a href="../index.html#type-t