 node of the tree.</span>
<span class="sd">        &quot;&quot;&quot;</span>
        <span class="c1"># Get the neighbor of the infinite node. Note we&#39;re assuming a single connected component so there&#39;s only one.</span>
        <span class="n">top_vertices</span> <span class="o">=</span> <span class="nb">list</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">predecessors</span><span class="p">(</span><span class="s1">&#39;v_inf&#39;</span><span class="