n class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">v</span><span class="special">)</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">v</span><span class="special">.</span><span class="identifier">is_red</span><span class="special">();</span> <span class="special">}),</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span cl