lass="sd">        &quot;&quot;&quot;</span>
        <span class="n">method</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">validate_derivatives_method</span><span class="p">(</span><span class="n">method</span><span class="p">,</span> <span class="n">attach</span><span class="p">)</span>

        <span class="c1"># If single system given, skip the parallelization</span>
        <span class="k">if</span> <span class="nb">isinstance</span><span class="p">(</