o">.</span><span class="n">_diffSets</span><span class="p">[</span><span class="n">item2</span><span class="p">][</span><span class="mi">1</span><span class="p">]</span><span class="o">.</span><span class="n">difference</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_diffSets</span><span class="p">[</span><span class="n">item1</span><span class="p">][</span><span class="mi">1</span><span class="p">])</span>
                    <span class="n">unionSup</span