<?xml version="1.0" encoding="UTF-8"?>
<users>
    <user name="Mariano" age="31">Achaval</user>
    <user age="31">Cantos</user>
    <country>Arg</country>
    <country xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:nil="true"></country>
</users>