tifier">map</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">char</span><span class="special">&gt;)</span></code>. Finally, the type of the first argument
      <code class="computeroutput"><span class="identifier">arg1_type</span></code> is extracted at compile-time
      using the <code class="computeroutput"><span class="identifier">function_traits</span></code> meta-function
      therefore obtaining the original type from the pa