from odoo import models, fields , api

class product_template(models.Model):

_inherit = 'product.template'

remise = fields.float('remise du fournisseur', size=10, required=True)

marge = fields.float('marge', size=10, required=True)

 @api.multi

@api.onchange('standard_price','x_marge1')

def onchange_calculer(self):

for s in self:

s.list_price = s.standard_price * (s.x_marge1/100) + s.standard_price

< my xml view file code

<!-- inherit the product form view -->

<record id="view_product_form" model="ir.ui.view">

<field name="name">product.template.common.form</field>

<field name="model">product.template</field>

<field name="inherit_id" ref="product.product_template_form_view"/>

<field name="arch" type="xml">

<xpath expr="//field[@name='list_price']" position="after">

<field name="x_remise1"/>

<field name="x_marge1"/>

<field name="list_price"

on_change="onchange_calculer(standard_price, x_marge1)" readonly="True" />

</xpath>

</field>

</record>