ed.  If <code>j</code> is not provided, or is the string <code>""</code>, then
<code>i</code> is sought in the <code>metadata</code> slot, and then in the <code>data</code> slot, returning
whichever is found first.  In other words, if <code>j</code> is not provided, the
<code>metadata</code> slot takes preference over the <code>data</code> slot. However, if <code>j</code> is
provided, then it must be either the string <code>"metadata"</code> or <code>"data"</code>, and it
directs where to look.</p></li>
<li