/span><span class="n">copy</span><span class="p">()</span>
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<div class="input_area highlight-ipython3 notranslate"><div class="highlight"><pre><span></span><span class="n">df</span><span class="p">[</span><span class="s2">&quot;nobs&quot;</span><span class="p">]</span> <span class="o">=</span> <span class="p">(</span><span