pan class="p">]:</span>
                        <span class="n">specials</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">node</span><span class="p">)</span>

        <span class="c1"># Condition two: carbon-carbon double &amp; triple bonds</span>
        <span class="k">for</span> <span class="n">node</span> <span class="ow">in</span> <span class="n">carbons</span><span class="p">:</span>
            <span class="n">neighbors</span> <span class="o">=</span> <s