lass="o">.</span><span class="n">matrix</span><span class="p">[</span><span class="n">key</span><span class="p">]</span>
            <span class="n">subkeyStr</span> <span class="o">=</span> <span class="s2">&quot; &quot;</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="sa">f</span><span class="s2">&quot;</span><span class="si">{</span><span class="n">subkey</span><span class="si">}</span><span class="s2">:</span><span class="si">{</span><span class="n">count</sp