a href="#toc_api-overview">API Overview</a>
        </li>
        <li>
          <a href="#toc_iterating-over-an-enumerable">Iterating Over an Enumerable</a>
        </li>
        <li>
          <a href="#toc_first-and-last-objects">First and Last Objects</a>
        </li>
        <li>
          <a href="#toc_map">Map</a>
        </li>
        <li>
          <a href="#toc_filtering">Filtering</a>
        </li>
        <li>
          <a href="#toc_aggregate-information-every-or-any">Aggregate Information (Ev