an class="special">::</span><span class="identifier">tuple</span><span class="special">&lt;</span><span class="identifier">T1</span><span class="special">,</span>
                    <span class="identifier">T2</span><span class="special">,</span>
                    <span class="special">...&gt;</span></code>
                  </p>
                </td>
<td>
                  <p>
                    Invoke the <code class="computeroutput"><span class="identifier">clear_value</span></code>
                 