title: Unescaped '<' not allowed in attributes values
body: <p>I am trying to add an XML <code>attrs</code> attribute that contains a <code>&lt;</code> character:</p>
  <pre><code>&lt;field name=&quot;discovery_note2&quot; nolabel=&quot;1&quot; placeholder=&quot;Note 2&quot;
         attrs=&quot;{'invisible': ['|', ('is_discovery', '=', False), ('note_amount', '&lt;', 0)]}&quot;/&gt;
  </code></pre>
  <p>But I am getting this error:</p>
  <blockquote>
  <p>Error: XMLSyntaxError: Unescaped '&lt;' not allowed in attributes values,</p>
  </blockquote>
  <p>How can I pass the condition, if the <code>note_amount</code> field value is less than zero, then it should be invisible.</p>
  <p>Note: <code>note_amount</code> is a computed field.</p>