pan class="identifier">space</span><span class="special">;</span>

    <span class="keyword">auto</span> <span class="identifier">push_back</span> <span class="special">=</span> <span class="special">[&amp;](</span><span class="keyword">auto</span><span class="special">&amp;</span> <span class="identifier">ctx</span><span class="special">){</span> <span class="identifier">v</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">_at