pan class="o">.</span><span class="n">_memoryRSS</span> <span class="o">=</span> <span class="nb">float</span><span class="p">()</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">_dbLen</span> <span class="o">=</span> <span class="mi">0</span>

    <span class="k">def</span> <span class="nf">_compareItems</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">o1</span><span class="p">,</span> <span class="n">o2</span><span class="p