stract">
                        <p>Advance to the next element and return it, or return <code>nil</code> if no next element exists.</p>

<div class="aside aside-complexity">
    <p class="aside-title">Complexity</p>
    Amortized O(1)

</div>

                      </div>
                      <div class="declaration">
                        <h4>Declaration</h4>
                        <div class="language">
                          <p class="aside-title">Swift</p>
                          <pre class="h