           </li>
                    </ul>
                  </li>
                </ul>
              </li>
            </ul>
          </li>

          <li><code>nonNegativeInteger</code>, which can be further defined as one of
              <ul>
                <li><code>positiveInteger</code></li>
                <li><code>unsignedLong</code>, even further describable as
                  <ul>
                    <li><code>unsignedInt</code>, with a subtype 
                     <ul>
                   