 class="p">,</span> <span class="k">const</span> <span class="n">Person</span><span class="o">&amp;</span> <span class="n">b</span><span class="p">)</span> <span class="p">{</span>
            <span class="k">return</span> <span class="n">a</span><span class="p">.</span><span class="n">year_of_birth</span> <span class="o">&lt;</span> <span class="n">b</span><span class="p">.</span><span class="n">year_of_birth</span><span class="p">;</span>
          <span class="p">});</span>
</pre></div>
</div>
<p>We can 