n class="o">=</span> <span class="n">g</span><span class="o">.</span><span class="n">op</span><span class="p">(</span><span class="s1">&#39;Abs&#39;</span><span class="p">,</span> <span class="n">x</span><span class="p">)</span>
        <span class="n">sign</span> <span class="o">=</span> <span class="n">g</span><span class="o">.</span><span class="n">op</span><span class="p">(</span><span class="s1">&#39;Sign&#39;</span><span class="p">,</span> <span class="n">x</span><span class="p">)</span>
        <span