ss="special">,</span><span class="identifier">S1</span><span class="special">,</span><span class="identifier">S2</span><span class="special">&gt;;</span>

<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">Q1</span><span class="special">,</span><span class="keyword">class</span> <span class="identifier">Q2</span><span class="special">&gt;</span> <span class="keyword">class</span> <span class="identifier">conversion_helper</span><