 class="p">):</span>
            <span class="n">system</span> <span class="o">=</span> <span class="n">System</span><span class="o">.</span><span class="n">from_atoms</span><span class="p">(</span><span class="n">system</span><span class="p">)</span>

        <span class="n">i_atomic_numbers</span> <span class="o">=</span> <span class="nb">set</span><span class="p">(</span><span class="n">system</span><span class="o">.</span><span class="n">get_atomic_numbers</span><span class="p">())</span>
        <span 