<?xml version="1.0" encoding="UTF-8"?>
<root xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <!-- Nillable, but not nilled -->
  <element1>1</element1>
  
  <!-- Nillable and nilled -->
  <element2 xsi:nil="true"/>
  
  <!-- Not nillable, and obviously not nilled (it would give a validation error)-->
  <element3>42</element3>
  
  <!-- Not processed / validated, and so never nill -->
  <element4 xsi:nil="true">42</element4>
</root>