bemade-addons/bemade_fsm/reports/worksheet_custom_reports.xml

<?xml version="1.0" encoding="utf-8" ?>
<odoo>
    <data>
        <record id="industry_fsm_report.task_custom_report" model="ir.actions.report">
            <field name="print_report_name">'%s %s' % (
                object.planned_date_begin.strftime('%Y-%m-%d') if object.planned_date_begin else time.strftime('%Y-%m-%d'),
                object.name
            )
            </field>
        </record>
    </data>
</odoo>