const</span> <span class="identifier">MyClass</span> <span class="special">&amp;</span><span class="identifier">o</span><span class="special">)</span>
<span class="special">{</span>  <span class="identifier">vector_</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">o</span><span class="special">);</span>  <span class="special">}</span>

<span class="keyword">const</span> <span class="identifier">MyClass</span> <span class="spe