n><span class="o">.</span><span class="n">_periodic</span> <span class="o">=</span> <span class="n">value</span>

    <span class="k">def</span> <span class="nf">_set_species</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">species</span><span class="p">):</span>
<span class="w">        </span><span class="sd">&quot;&quot;&quot;Used to setup the species information for this descriptor. This</span>
<span class="sd">        information includes an ordered list