pan> <span class="keyword"></span> <span class="identifier">fusion</span><span class="special">::</span><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">at</span><span class="special">&lt;</span>
      <span class="keyword">typename</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">remove_reference</span><span class="special">&lt;</span><span class="identifier">Seq</span><span class="special">&gt;</span><span c