">(</span><span class="bp">self</span><span class="p">):</span>
    <span class="sd">&quot;&quot;&quot;</span>
<span class="sd">    Obtain version of Valued with negative values (e.g. -xt). </span>

<span class="sd">    Returns:</span>
<span class="sd">      Valued copy with value is -self.value</span>
<span class="sd">    &quot;&quot;&quot;</span>

    <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">copy</span><span class="p">(</span><span class="n">value</