n class="o">+</span> <span class="mi">1</span><span class="p">),</span> <span class="n">unique_elements</span><span class="p">)</span>
        <span class="p">)</span>
        <span class="n">species</span> <span class="o">=</span> <span class="p">[</span><span class="n">element_map</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="bp">self</span><span class="p">[</span><span class="s2">&