<span class="p">(</span><span class="n">new_atom</span><span class="p">,</span> <span class="n">atom_cluster</span><span class="p">)</span>
        <span class="k">return</span> <span class="n">atom_cluster</span>

    <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="nb">range</span><span class="p">(</span><span class="n">n_atoms</span><span class="p">):</span>
        <span class="k">if</span> <span class="ow">not</span> <span class="n">visited</span><span class="