<?xml version="1.0"?>
<form>
                <group>
                    <field name="name" placeholder="e.g. Conference for Architects"/>
                    <field name="date_begin" string="Date" widget="daterange" options="{'end_date_field': 'date_end'}"/>
                    <field name="date_end" invisible="1"/>
                </group>
            </form>
        