<span class="special">&amp;&amp;</span> ds1<span class="special">,</span> <span class="identifier">DataSet2</span> <span class="special">&amp;&amp;</span> ds2<span class="special">)</span><span class="special">;</span>
        <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> DataSet1<span class="special">,</span> <span class="keyword">typename</span> DataSet2<span class="special">&gt;</span> 
          <span class="identifier">boost</span><span clas