n><span class="special">,</span> <span class="keyword">const</span> <span class="identifier">element_type</span> <span class="special">&amp;</span><span class="special">)</span><span class="special">;</span>
  <span class="special">}</span><span class="special">;</span>
  <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> Type<span class="special">&gt;</span> 
  <span class="keyword">struct</span> <a class="link" href="map/on_invertible_Typ_id672601.h