"><p>fold over exceptional predescessors</p></div></div><div class="odoc-spec"><div class="spec value anchored" id="val-start_node"><a href="#val-start_node" class="anchor"></a><code><span><span class="keyword">val</span> start_node : <span><a href="#type-t">t</a> <span class="arrow">&#45;&gt;</span></span> <a href="Node/index.html#type-t">Node.t</a></span></code></div></div><div class="odoc-spec"><div class="spec value anchored" id="val-exit_node"><a href="#val-exit_node" class="anchor"></a><code><span><sp