n><span class="n">append</span><span class="p">(</span><span class="n">itemJ</span><span class="p">)</span>
                    <span class="n">classTidSets</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">y</span><span class="p">)</span>
            <span class="n">newPrefix</span> <span class="o">=</span> <span class="nb">list</span><span class="p">(</span><span class="nb">set</span><span class="p">(</span><span class="n">itemSetX</span><span class="p">))<