n class="n">compare</span><span class="p">(</span><span class="n">ref</span><span class="p">,</span> <span class="n">timespan</span><span class="o">=</span><span class="p">(</span><span class="mi">1801</span><span class="p">,</span> <span class="mi">1900</span><span class="p">))</span><span class="o">.</span><span class="n">plot_qs</span><span class="p">()</span>
<span class="n">ax</span><span class="o">.</span><span class="n">set_xlim</span><span class="p">(</span><span class="mi">1800</span><span class="p