pan class="keyword">template</span> <span class="special">&lt;</span>
    <span class="keyword">class</span> <span class="identifier">Derived</span>
  <span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Base</span>
  <span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Value</span>               <span class="special">=</span> <span class="identifier">use_default</span>
  <span class="special">,</span> <span class="keyword">class</s