tl-data-engineering-verified">1. ETL / Data Engineering (Verified)</h2>
<p><strong>Example: Count lines in multiple CSV files</strong>
<div class="highlight"><pre><span></span><code><span class="kn">import</span><span class="w"> </span><span class="nn">grapapy</span>
<span class="n">xy</span> <span class="o">=</span> <span class="n">grapapy</span><span class="o">.</span><span class="n">grapa</span><span class="p">()</span>

<span class="n">files</span> <span class="o">=</span> <span class="p">[</span><span 