<university>
 <name>UC Berkeley</name>
 <department>
  <name>SIMS</name>
  <class id="290-4">
     <student><name>Jane Smith</name></student>
     <student><name>John Doe</name></student>
  </class>
  <class id="290-8">
     <student><name>Jane Smith</name></student>
  </class>
 </department>
</university>

...but 'student' gets duplicated.