pan><span class="mi">1</span><span class="p">),</span> <span class="n">usecols</span><span class="o">=</span><span class="p">[</span><span class="mi">4</span><span class="p">,</span><span class="mi">5</span><span class="p">,</span><span class="mi">6</span><span class="p">])</span>
    <span class="n">count</span> <span class="o">=</span> <span class="mi">0</span>

    <span class="k">while</span> <span class="p">(</span><span class="n">count</span> <span class="o">&lt;</span> <span class="n">n_nuc</span><sp