span><span class="special">&gt;()</span></code>
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">bm_type</span><span class="special">::</span><span class="identifier">left_map</span></code>
                </p>
              </td>
<td>
                <p>
                  <code class="computeroutput"><span class="identifier">bm</span><span class="special">::</span><span class="identifier">map_by</span><span 