pe extends from the base
          <code><a>Collection</a></code> type and inherits all of it's
          properties. The following additional properties can also be
          specified:
          <code>
            <a href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-partof">partOf</a> |
            <a href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-next">next</a> |
            <a href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-prev">prev</a> |
          </code>
        </