/span>
    <span class="keyword">class</span> <span class="identifier">F</span><span class="special">,</span>
    <span class="keyword">class</span> <span class="identifier">String</span><span class="special">&gt;</span>
<span class="keyword">bool</span>
<span class="identifier">unexcept</span><span class="special">(</span>
    <span class="identifier">F</span><span class="special">&amp;&amp;</span> <span class="identifier">f</span><span class="special">,</span>
    <span class="identifier">String</span> <s