an> <span class="o">=</span> <span class="n">df</span><span class="o">.</span><span class="n">columns</span>
    <span class="n">np</span><span class="o">.</span><span class="n">fill_diagonal</span><span class="p">(</span><span class="n">df</span><span class="o">.</span><span class="n">values</span><span class="p">,</span> <span class="mi">0</span><span class="p">)</span>
    
    <span class="n">fig</span><span class="p">,</span> <span class="n">ax</span> <span class="o">=</span> <span class="n">plt</span>