">
              </ul>
            </li>
            <li class="nav-item" data-level="3"><a href="#example-4-bandpass" class="nav-link">Example 4: bandpass</a>
              <ul class="nav flex-column">
              </ul>
            </li>
            <li class="nav-item" data-level="3"><a href="#example-5-resonant" class="nav-link">Example 5: resonant</a>
              <ul class="nav flex-column">
              </ul>
            </li>
            <li class="nav-item" data-level="3"><a href="#example-6-fir