fier">type</span> 
  <span class="identifier">extract_or_default</span><span class="special">(</span><a class="link" href="attribute_name.html" title="Class attribute_name">attribute_name</a> <span class="keyword">const</span> <span class="special">&amp;</span> name<span class="special">,</span> 
                     <a class="link" href="attribute_value_set.html" title="Class attribute_value_set">attribute_value_set</a> <span class="keyword">const</span> <span class="special">&amp;</span> attrs<span class=