de>. </span>

        <span class="comment">// Set union of the axis option arguments. </span>
        <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">unsigned</span> B1<span class="special">,</span> <span class="keyword">unsigned</span> B2<span class="special">&gt;</span> 
          <span class="keyword">constexpr</span> <span class="keyword">auto</span> <a name="boost.histogram.axis.option.operator_idm45105994963232"></a><span class="keyword">operator</span><spa