     <a id="ember168936" class="ember-view active" data-test-toc-link="Computed Properties and Aggregate Data" href="/v2.18.0/object-model/computed-properties-and-aggregate-data">
            <span class="link-text">
              Computed Properties and Aggregate Data
            </span>
          </a>
        </li>
              <li class="toc-item toc-link ">
          <a id="ember168937" class="ember-view" data-test-toc-link="Observers" href="/v2.18.0/object-model/observers">
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