n class="s2">&quot;</span>,<span class="s2">&quot;</span><span class="s">def</span><span class="s2">&quot;</span>,<span class="s2">&quot;</span><span class="s">ghi</span><span class="s2">&quot;</span>]<span class="ss">)</span>
 <span class="k">end</span> <span class="nv">program</span> <span class="nv">demo_upper</span>

<span class="nv">Expected</span> <span class="nv">output</span>

 <span class="nv">mixed</span><span class="o">-</span><span class="nv">case</span> <span class="nv">input</span> <span class