r2 = <a href="#type-iterator">iterator</a>(B)</tt></li><li><tt>Iterator3 = <a href="#type-iterator">iterator</a>(A | B)</tt></li></ul></p>
<p> </p>
</div><p><p>
  Returns the sorted iterator formed by merging <code>Iterator1</code> and
  <code>Iterator2</code>. Both <code>Iterator1</code> and <code>Iterator2</code> must be sorted
  according to the ordering function <code>Fun</code> before evaluating this
  function. <code>Fun(A, B)</code> is to return <code>true</code> if <code>A</code> compares less than
