ass="p">(</span><span class="bp">self</span><span class="p">):</span>
        <span class="sd">&quot;&quot;&quot;</span>
<span class="sd">        return a list of the keys... most frequent first</span>
<span class="sd">        &quot;&quot;&quot;</span>
        <span class="n">keylist</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">frequency_list</span><span class="p">()</span>
        <span class="n">keylist</span><span class="o">.</span><span class="n">so