l">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="keyword">operator</span><span class="special">()(</span><span class="identifier">T</span><span class="special">)</span> <span class="keyword">const</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">std</span><span class="speci