<code>  <span class="nv">upper</span><span class="ss">(</span><span class="nv">string</span><span class="ss">)</span> <span class="nv">returns</span> <span class="nv">a</span> <span class="nv">copy</span> <span class="nv">of</span> <span class="nv">the</span> <span class="nv">input</span> <span class="nv">string</span> <span class="nv">with</span> <span class="nv">all</span> <span class="nv">characters</span>
  <span class="nv">converted</span> <span class="nv">in</span> <span class="nv">the</span> <span cl