t of sets of ints, representing groups of connected atoms</span>
<span class="sd">        &quot;&quot;&quot;</span>

        <span class="n">heteroatoms</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">get_heteroatoms</span><span class="p">(</span><span class="n">elements</span><span class="o">=</span><span class="n">elements</span><span class="p">)</span>
        <span class="n">special_cs</span> <span class="o">=</span> <span class="bp">self</span><span c