<td>
  Returns an iterator of tuples where, for each tuple in
  <code>TupleIterator1</code>, the <code>N</code>th element <code>Term1</code> of the tuple has been
  replaced with the result of calling <code>Fun(Term1)</code>.</td></tr>
<tr><td valign="top"><a href="#keymember-3">keymember/3</a></td><td>
  Returns <code>true</code> if there is a tuple in <code>TupleIterator</code> whose <code>N</code>th
  element compares equal to <code>Key</code>, otherwise <code>false</code>.</td></tr>
<tr><td valign="top"