tor</a>(Elem2)</tt></li><li><tt>TupleIterator3 = <a href="#type-iterator">iterator</a>(Elem1 | Elem2)</tt></li><li><tt>Elem1 = tuple()</tt></li><li><tt>Elem2 = tuple()</tt></li></ul></p>
<p> </p>
</div><p><p>
  Returns the sorted iterator formed by merging <code>TupleIterator1</code> and
  <code>TupleIterator2</code>. The merge is performed on the <code>N</code>th element of each
  tuple. Both <code>TupleIterator1</code> and <code>TupleIterator2</code> must be key-sorted without
  duplicates before evaluati