fetchmail_view.xml

<?xml version="1.0"?>
<odoo>

    <record id="view_email_server_form_e_invoice" model="ir.ui.view">
        <field name="name">view_email_server_form_e_invoice</field>
        <field name="model">fetchmail.server</field>
        <field name="inherit_id" ref="fetchmail.view_email_server_form"/>
        <field name="arch" type="xml">
            <notebook position="inside">
                <page string="Last error message" attrs="{'invisible': [('last_pec_error_message', '=', False)]}">
                    <field name="last_pec_error_message"/>
                </page>
            </notebook>
            <xpath expr="//notebook/page[1]/group[1]/group[3]" position="attributes">
                <!-- Hiding, because it would not be considered. See 'fetch_mail' override -->
                <attribute name="attrs">{'invisible': [('is_fatturapa_pec', '=', True)]}</attribute>
            </xpath>
        </field>
    </record>
</odoo>