   data: it computes the new position of each group on the Y
                    axis
                  </li>
                  <br />
                  <li>
                    The output of <code>d3.stack()</code> can be used to create
                    a set of <code>rect</code> as for a normal barplot.
                  </li>
                </ul>
              </div>
            </div>
          </div>

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