 <span class="o">==</span> <span class="kc">None</span><span class="p">:</span>
            <span class="n">key</span> <span class="o">=</span> <span class="nb">max</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">labels</span><span class="o">.</span><span class="n">keys</span><span class="p">())</span> <span class="o">+</span> <span class="mi">1</span>
        <span class="k">elif</span> <span class="n">label</span> <span class="ow">in</span> <span class="bp