n class="identifier">DataSet1</span> <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">namespace</span> <span class="identifier">result_of</span> <span class="special">{</span>
          <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> DataSet1Gen<span c