<?xml version="1.0" encoding="UTF-8" ?>
<node id="grandparent">
    <attr id="title">Grandparent title</attr>
    <node id="parent">
        <attr id="title">Parent title</attr>
        <attr id="valid_url">https://www.athena-innovation.gr/</attr>
        <attr id="invalid_url">https://www.athena-innovation.gr/invalid</attr>
        <attr id="mixed_valid_url">https://www.athena-innovation.gr/</attr>
        <node id="child">
            <attr id="title">Child title</attr>
            <attr id="valid_url">https://www.athena-innovation.gr/el/contact</attr>
            <attr id="invalid_url">not_a_url</attr>
            <attr id="mixed_valid_url">invalid_url</attr>
            <attr id="single_valid_url">https://www.athena-innovation.gr/</attr>
        </node>
    </node>
</node>