 <span class="o">=</span> <span class="p">[</span><span class="s1">&#39;x&#39;</span><span class="p">,</span> <span class="s1">&#39;y&#39;</span><span class="p">]</span> <span class="o">+</span> <span class="nb">list</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">df</span><span class="o">.</span><span class="n">columns</span><span class="p">[</span><span class="mi">2</span><span class="p">:])</span>
        <span class="bp">self</span><span class="o">.</spa