Here is an example, in purchase_view.xml in purchase module

<notebook>
                        <page string="Purchase Order">
                            <field name="order_line">
                                <tree string="Purchase Order Lines" editable="bottom">
                                    <field name="product_id" on_change="onchange_product_id(parent.pricelist_id,product_id,0,product_uom,parent.partner_id, parent.date_order,parent.fiscal_position,date_planned,name,price_unit,context)"/>
                                    <field name="name"/>
                                    <field name="date_planned"/>
                                    <field name="company_id" groups="base.group_multi_company" widget="selection"/>
                                    <field name="account_analytic_id" groups="purchase.group_analytic_accounting" domain="[('type','not in',('view','template'))]"/>
                                    <field name="product_qty" on_change="onchange_product_id(parent.pricelist_id,product_id,product_qty,product_uom,parent.partner_id,parent.date_order,parent.fiscal_position,date_planned,name,price_unit,context)"/>
                                    <field name="product_uom" groups="product.group_uom" on_change="onchange_product_uom(parent.pricelist_id,product_id,product_qty,product_uom,parent.partner_id, parent.date_order,parent.fiscal_position,date_planned,name,price_unit,context)"/>
                                    <field name="price_unit"/>
                                    <field name="taxes_id" widget="many2many_tags" domain="[('parent_id','=',False),('type_tax_use','!=','sale')]"/>
                                    <field name="price_subtotal"/>
                                </tree>
                            </field>
                            </page>
                    </notebook>