           
        <span class="n">ax</span><span class="o">.</span><span class="n">plot</span><span class="p">(</span><span class="mi">0</span><span class="p">,</span><span class="mi">0</span><span class="p">,</span><span class="n">color</span> <span class="o">=</span> <span class="s1">&#39;grey&#39;</span><span class="p">,</span><span class="n">marker</span> <span class="o">=</span> <span class="s1">&#39;+&#39;</span><span class="p">,</span><span class="n">linestyle</span> <span class="o">=</span> <span 