ription</a>
        </h6>
<p>
          If the key equivalent to <code class="computeroutput"><span class="identifier">key</span></code>
          already exists in the container. assigns <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">forward</span><span class="special">&lt;</span><span class="identifier">M</span><span class="special">&gt;(</span><span class="identifier">obj</span><span class="special">)</span></code> to the <code clas