<?xml version="1.0"?>
<tree decoration-danger="state=='error'" decoration-muted="state=='sent'" string="Letters">
                <field name="attachment_id" string="Document"/>
                <field name="partner_id"/>
                <field name="user_id"/>
                <field name="state" invisible="1"/>
                <field name="info_msg" widget="html"/>
                <field name="company_id" groups="base.group_multi_company"/>
            </tree>
        