s="p">)</span>
        <span class="k">if</span> <span class="n">return_descriptor</span><span class="p">:</span>
            <span class="n">des_lists</span> <span class="o">=</span> <span class="p">[</span><span class="n">x</span><span class="p">[</span><span class="mi">0</span><span class="p">][</span><span class="mi">1</span><span class="p">]</span> <span class="k">for</span> <span class="n">x</span> <span class="ow">in</span> <span class="n">vec_lists</span><span class="p">]</span>
            <span cl