 <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>
        <span class="n">index_path</span> <span class="o">=</span> <span class="sa">f</span><span class="s1">'</span><span class="si">{</span><span class="n">base_directory</span><span class="si">}</span><span class="s1">/.index/</span><span class="si">{</span><span class="n">search_class</span><span class="si">}</span><span class="s1">.txt'</span>
    <span class="k">else</span><span class="p">:</span>
        <span class="n">