I am trying to write a parser (render_html) for a custom template which inherits report.minimal_layout without sucess.

I can write parsers (render_html) for other templates.

This is my template:

<template id="report_saleorder_css" inherit_id="report.minimal_layout">
    <xpath expr="html/head/*[position() = last()]" position="after">
        <span>AAA</span><span><t t-esc="css_file" /></span><span>BBB</span>
    </xpath>
</template>

I would like to write a parser that passes css_file as variable.

Please avoid standard non-tested answers, as mentioned, I already tried the standard parser from Odoo documentation and it did not work, and I can perfectly write parsers for other templates. I begin to suspect that templates belonging to report (and inherited ones) are outside the scope of custom classes with render_html. Thanks