span class="special">,</span> <span class="keyword">typename</span> Compare <span class="special">=</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">less</span><span class="special">&lt;</span><span class="identifier">Key</span><span class="special">&gt;</span><span class="special">,</span> 
         <span class="keyword">typename</span> Allocator <span class="special">=</span> <span class="identifier">std</span><span class="special">::</span><span class="ide