"sd">            respectively.</span>
<span class="sd">        &quot;&quot;&quot;</span>
        <span class="n">symmetric</span> <span class="o">=</span> <span class="kc">False</span>
        <span class="k">if</span> <span class="n">y</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>
            <span class="n">y</span> <span class="o">=</span> <span class="n">x</span>
            <span class="n">symmetric</span> <span class="o">=</span> <span class="kc">True</span>

 