>Iterator1</code> starting at <code>Start</code> and with
  (maximum) <code>Len</code> elements.</td></tr>
<tr><td valign="top"><a href="#subtract-2">subtract/2</a></td><td>
  Returns a new iterator <code>Iterator3</code> that is a copy of <code>Iterator1</code>,
  subjected to the following procedure: for each element in
  <code>Iterator2</code>, its first occurrence in <code>Iterator1</code> is deleted.</td></tr>
<tr><td valign="top"><a href="#suffix-2">suffix/2</a></td><td>
  Returns <code>true</code> if