bemade-addons/bemade_fsm/reports/worksheet_custom_reports.xml

<?xml version="1.0" encoding="utf-8" ?>
<odoo>
    <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>
</odoo>