ogram</span> <span class="special">&amp;</span><span class="special">,</span> <span class="keyword">const</span> <a class="link" href="../boost/histogram/algorithm/reduce_option.html" title="Struct reduce_option">reduce_option</a> <span class="special">&amp;</span><span class="special">,</span> <span class="identifier">Ts</span> <span class="special">&amp;&amp;</span><span class="special">...</span><span class="special">)</span><span class="special">;</span>
    <span class="special">}</span>
  <span class=