="n">tpdv</span><span class="p">)</span>
        <span class="bp">self</span><span class="o">.</span><span class="n">scale</span> <span class="o">=</span> <span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">high</span> <span class="o">-</span> <span class="bp">self</span><span class="o">.</span><span class="n">low</span><span class="p">)</span> <span class="o">/</span> <span class="mi">2</span>
        <span class="bp">self</span><span class="o">.</span><span class="n