/span></em><span class="sig-paren">)</span> &#x2192; <a class="reference external" href="https://docs.python.org/3/library/constants.html#None" title="(in Python v3.9)">None</a><a class="headerlink" href="#dscribe.ext.SOAPPolynomial.derivatives_numerical" title="Permalink to this definition">¶</a></dt>
<dd></dd></dl>

</dd></dl>

<dl class="py function">
<dt id="dscribe.ext.extend_system">
<code class="sig-prename descclassname">dscribe.ext.</code><code class="sig-name descname">extend_system</code><span c